EPA-902/9-75-001
November 1975 Cornell University
Proceedings of a
Conference on Emerging
Environmental Problems
Acid Precipitation
Sponsored by
New York State Department of Environmental Conservation
United States Environmental Protection Agency, Region II
Water Resources and Marine Sciences Center, Cornell University
Center for Environmental Quality Management, Cornel! University
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PROCEEDINGS OF A CONFERENCE ON EMERGING
ENVIRONMENTAL PROBLEMS:
ACID PRECIPITATION
May 19-20, 1975
The Institute on Man and Science
Rensselaerville, New York
Published by the
U.S. Environmental Protection Agency, Region II
Gerald M. Hansler, P.E.
Regional Administrator
The contents of these proceedings do not necessarily reflect the views and
policies of the Environmental Protection Agency nor does mention of trade
names or commercial products constitute endorsement or recommendation for
use.
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CONFERENCE OBJECTIVES
Because o^ the. pcttntiaJL long-te.fim e.ccloglcal and health
Ldlth the. -oic-tea-ie In acidity o& precipitation In fie.ce.nt ye.au,
Reg-con II, Env Ce.nte.fi and Ce.nte.fi {.on. Env-ln.ome.ntai Quality Manage-
ment afie. Apon&ofLLng ttilb Confie.fie.nce. to In&ofun 4 e.le.cte.d e-nv-lwme.ntal
age.ncle.6, lnduAtfu.e.4, and public Intz-ie-^t gfioupA ofi the. phe.nome.non and
cu.fifie.nt knowledge, ofi the. eao'
This Conference was supported in part with funds provided by the Zurn
Foundation, Erie, Pennsylvania, and by the U.S. Department of the Interior,
Office of Water Research and Technology, pursuant to the Water Resources
Research Act of 1964 as amended.
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TABLE OF CONTENTS
WELCOME 1
Herbert Posner
INTRODUCTORY REMARKS 2
Eric Outwater
Ogden R. Reid
ACID PRECIPITATION: A WORLD CONCERN
Keynote Address 5
Svante Oden
Plenary Session I
ACID PRECIPITATION: OUR UNDERSTANDING OF THE PHENOMENON. ... 45
Gene E. Likens
ACID PRECIPITATION: OUR UNDERSTANDING OF THE ECOLOGICAL
EFFECTS 76
Carl L. Schofield
HEALTH EFFECTS OF ACID AEROSOLS 88
Jean G. French
Plenary Session II
DISCUSSION SESSION ON THE PHENOMENON 96
John Hawley, Discussion Leader
James Galloway, Rapporteur
DISCUSSION SESSION ON THE ECOLOGICAL EFFECTS 99
Jay Jacobson, Discussion Leader
Don Charles, Rapporteur
DISCUSSION SESSION ON HEALTH EFFECTS 105
Donald Casey, Discussion Leader
Walter Lynn, Rapporteur
PARTICIPANTS 107
PROGRAM 113
111
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WELCOME
Herbert Posner*
Mr. Posner, in welcoming the participants to the Conference, made
special mention of those from out of the country and out of the State.
He expressed pleasure that the Conference includes scientists from out-
side the United States since acid precipitation is an international
problem. Mr. Posner also expressed the hope that the approach being taken
here to determine the parameters of the problem and possible solutions
will become a model to assist decision makers in finding appropriate
technological, social and economic solutions to important problems.
He emphasized the difficulty faced by the Legislature and especially
the Environmental Conservation Committee in keeping up to date and informed
about the multitude of environmental problems, such as Freon and ozone,
LNG storage, sludge, carcinogens in drinking water, and acid precipitation.
Mr. Posner lauded the competence of the Assembly Scientific Staff in
providing the needed technical assistance to the Assembly.
*Chairman, Environmental Conservation Committee, New York State Assembly,
State Capitol, Albany, New York 12224
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INTRODUCTORY REMARKS
Eric Outwater*
Mr. Outwater briefly touched on some of the important environmental
problems which are of particular concern to EPA and EPA's commitment to
solve them. In addition to its pollution abatement and control activities,
which involve research, monitoring, standards setting, and enforcement,
EPA coordinates and supports research activities by State and local govern-
ments, and private and public groups. Mr. Outwater expressed gratification
for the cooperation received from the N.Y.S. Department of Environmental
Conservation on issues with which the two agencies worked together.
*Deputy Regional Administrator, Region II, U.S. Environmental Protection
Agency.
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Ogden R. Reid*
I would like to welcome all of you from different parts of the country
and Europe. Dr. Oden, you have helped lead the world in important directions
and we're very grateful for the opportunity of having you here.
I judge many of you attended the First International Symposium on
Acid Precipitation recently held in Ohio. I've heard brief reports about
it, and that the European representation was particularly creative and
helpful. My understanding is that in Scandinavia, using lichens as a test
for sulfur oxides in the air provides yet another example of the importance
to man of every manifestation of nature. I certainly want to thank you
for your pioneering effort.
One thing that I think has struck all of us is that our flora, fauna,
fish and forests provide early warninq of problems. I think that there
is some evidence that we are seeing some abnormalities on the leaves of
yellow birches; that pine needle lengths have varied in some areas of the
western Adirondacks, and certainly the life expectancy of fish in some of
the Adirondack lakes is very low. As all of you know, the latter is
probably related to the pH content in the lakes. We have found that the
pH in some of the lakes has gone from 5 to 3.5 on the pH scale. On this
scale, 1 is corrosive acid; 14 is corrosive alkali; 6 to 8 is considered
normal and "safe" for humans and animals.
It may be too early to make a judgment as to whether or not this is
characteristic of most of the lakes in the Adirondacks. However, in
sampling of water from 80 lakes, Schofield (Cornell) found that 35 were
*Commissi'oner, N.Y.S. Department of Environmental Conservation
3
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below 6 pH. Of these, 33 were in the western Adirondacks where precip-
itation is high and the lakes contain less soil and natural minerals
or buffering agents, such as lime or alkaline salts.
One of the problems is that the sources of pollutants are difficult
to trace and the transport mechanism is not clearly understood. It is
believed, however, that sulfur and nitrogen pollutants are coming from
industrial smokestacks, primarily in the Midwest and Canada.
The Department plans to initiate an interdisciplinary research
program to study these problems. In addition to air sampling to determine
the source of acids in the air, it is planned to take water samples from
large numbers of lakes in the Adirondacks and analyze their pH levels.
We thereby hope to determine the extent of the problem, the effects on
health, the environment and the economy, and possible solutions.
There are many other environmental problems which confront us such
as the Outer Continental Shelf, the stratosphere, carcinogenic inducing
substances, and land use, to name a few. Meetings such as this can be
valuable in developing parameters for scientific research.
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ACID PRECIPITATION: A WORLD CONCERN
Keynote Address
Svante Oden*
The Atmospheric Chemical Network in Europe
The increasing acidity of air and precipitation in Europe and its
consequences to soils, vegetation and surface waters were first presented
in a Swedish Governmental Report entitled Env-inonme.ntal ReieoAc/i (1967).
The basic facts in this report originated from long-term network data
regarding the chemistry of air and precipitation in Europe and to some
extent of surface waters in Scandinavia. At that time the records extended
for almost a 10 year period for certain areas in Europe. When plotting
these data for the different elements at individual stations it became
evident that certain elements showed either a positive or a negative
trend with respect to time. The chemical climate was obviously changing
in Europe. In order to study the effect on soils and surface waters (and
indirectly on vegetation) a surface water network was set up in
Scandinavia in 1961-62. My presentation today will be based mainly on
data from these two network systems.
Figure 1 illustrates the network in atmospheric chemistry. Each dot
represents a sampling station, where precipitation and air have been
sampled on a monthly basis. The major cations and anions have been
determined as well as pH and electrical conductivity. The network started
*Department of Soil Science, Division of Ecochemistry, Agricultural College
Uppsala, Sweden.
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Figure 1. Each dot on the map represents a sampling station for precipi-
tation and air. Part of the network is coordinated by the
International Meteorological Institute in Stockholm.
in Sweden in 1948, extended to the rest of Scandinavia in 1952-54, and
to the rest of Europe the years thereafter. As part of the program of
the geophysical year (1957) a one-year study was made in some countries.
The U.S.S.R. started a network over all Asia to the Pacific in 1958, and
to my knowledge this network is still operating. The Polish network
started in 1964. Data from the last two countries are available for
some years. Altogether these data makes it possible to evaluate changes
of the chemical climate in Europe at individual stations, and the
geographical distribution also. The network density of about 130 stations
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(at maximum level) is not dense enough, however, to evaluate the details.
The discontinuity between sea and land necessitates a much denser network
to give a true picture of the geographical distribution pattern. The
U.S. Continent is more homogeneous in this respect and the widespread
network that has existed now and then seems appropriate for mapping
atmospheric chemical constituents. The present drawback is the lack of
consistency with time.
Figure 2 illustrates the position and the intensity of the water
quality network in Sweden. In Finland and Norway similar networks are at
work. In the beginning the Swedish network operated with a limited
number of determinations but since 1965, eighteen elements or other
determinations have been made on every monthly sample. Since the water
flow is also determined, the discharge can be computed for every element.
By comparing the atmospheric fallout with the river discharge, the effect
of changes in the chemical climate can be determined. The influence of
farming, water pollution or other widespread or intense activities,
however, may distort such computations.
Figure 3 shows the time records of the fallout of nitrate (N0_) and
ammonia (NH.) from some stations of the European network. A more or less
continuous increase with time takes place, and the rate of this increase
is more pronounced at stations closer to the center of Europe. This is
therefore likely to be the source center for NO., and NH. in the atmosphere.
Data from the individual stations vary to some extent from year to year,
reflecting variations in both source and sink conditions and larqe-scale
meteorological interferences. Occasionally very high fiaures may appear
(cf NH.-N at fts in 1967 and 1972). Other stations show a wave-pattern
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Botorpstrommen
Hclgcan
Figure 2. The major lakes and rivers in Sweden. The dots show the
location of the sampling stations. Most of the network is
administrated by the Limnological Laboratory, Uppsala,
Environmental Protection Board of Sweden.
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3-N- ke/tu,r N»4-N-
1
8-
"
iN Amberieu (F)
A »•
// \
II \ Wineven (Neth.)
r/
u
61 Tx I 6-
/[ • s . Plonninge (Sw)
4^ ft /i /\ I 'H
, i\ / * *. ,«. / \ /
2
n
/ V" / *\ /•'' \«| As (N)
' .(A/A^V.»
'•**/ A A ' A 21
-^r !J V — •''"- ,«-V • Porshult (Sw)
;r^->'-^VV*"'
. n.
Askov (D)
/
/ A*
/ • M
r
A N
-A / A / J
~~~~ /*\.* ' • •
NI\ J
' . Plonninge
.*
/ \/V fVmknlr
rr_Tu/Vv/\/v--
-
I9W
I960 1970 feu
I9W
I960
Figure 3. Time records of the wet fallout of nitrate and ammonia at
some stations within the European network. The stations
vary latitudinally from 60 Degr. N (As and Forshult) to
46 Degr. N (Amberieu).
with simultaneous increasing or decreasing values (cf N03-N at Amberieu
and Witteven). This yearly variation occurs for almost every element
and points out the necessity of long-term records in order to determine
any trends in the data.
Nitrate in precipitation is basically man made. The increase in
Central Europe is very pronounced. In the middle of the nineteen fifties
the fallout was less than 2 kg/ha-year. Prior to 1950 the fallout of
NOo-N did not vary too much among different stations in Europe. The
baseline figure for all stations was likely to be around 1 kg/ha-year or
less. The very pronounced increase of NO--N is due to the large emissions
of NO from various industries, high temperature engines and oil-based
A
power plans. In the atmosphere NO is oxidized to nitric acid. This
X
compound consequently forms part of the atmospheric acidity.
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The station records for NH4-N indicate somewhat different figures.
Tie increase with time is not so pronounced and the background values for
the different stations seem to be fairly well separated, at least around
1950. Going further back in time these values may narrow, but it is
very unlikely that they will coincide for the Different stations in Europe.
The reason for this is that NH- is liberated from soils and eutrophicated
surface waters, giving rise to diffuse and local source areas. Such are
the intensely farmed (including cattle raising) parts of Europe and the
shelf areas of the North Sea. The increase of W.-f' during the last
decades reflects, too, the influence by man but Hi-^ferently from NCL-N.
Farming intensity has increased during this time (primarily because of
the use of fertilizers) and it is well known that the eutrophic level of
the North Sea as well as lakes and rivers in Europe has become higher.
Consequently the diffuse emissions of NH, has increased.
The wet fallout of total nitrogen forms a distinct pattern over
Europe. In 1958-59 (Figure 4) three areas with more than 8 kg/ha-year
appeared, and the fallout was reduced extending outwards from the Center
of Europe. In Northern Scandinavia the value was less than 1 kg/ha-year.
Ten years later there was an overall increase of the fallout by a factor
of 2. The concentric pattern, however, still exists. The data from
Polen have been extrapolated for the years 1968-69.
NH.-N takes part in the acidity problem in at least two ways. NH-
neutralizes acids formed when SCL is oxidized. This leads to enhanced
oxidation rate of SCL and consequently of the final oxidation product,
which is sulphuric acid. The increased emissions of NH- promotes the
formation of acids within a narrowing area. On the other hand, the acids
10
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Figure 4.
The maps show the qeooraphical distribution of the wet fallout of total nitronen (NO^-M and
MH.-N) for the averaged period 1958-59 in comparison with 1968-69. Finures are niven in
kg/ha-year.
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formed will be more or less neutralized from an atmospheric chemical point
of view. The acidifyinn effect of neutral or acid ammonium sulfate on
reservoirs like soils and surface waters, however, will be equally stronq
as that of the pure acid, since the ammonia part will be resorbed by the
plants. This forms part of the process I have called "biological
acidification."
Particles of (NH.L SO. or NH.H SO. formed in the atmosphere are very
small and consequently widespread. The net effect of counteractinq
processes of NH, can not be computed at present. The rapid increase of the
O
acidity of lakes and rivers in Scandinavia indicates, however, that both
the increase of the production of acids and the spreading of these acids
has enhanced the acidification of remote areas in Europe.
Other elements than NO.-N and NH.-N show time trends. Thus S and H
increases with time as will be discussed later. Cations like Ca, Mg and
K appear very irreqularly in the data. At some stations they increase with
time; at others they decrease. This state of contrast seems to be related
to local industrial activities qiving rise to increasing or decreasinn
emissions. The overall picture for Europe is a slight increase in the sum
of the above elements.
The elements Na and Cl form a very distinct geographical pattern for
Europe with high fallout figures along the marine shore lines. The picture
is equivalent for the United States and the relation of these elements to
marine salts is well known. There is no trend in the data of these elements,
but there may be a periodic variation with a time period of 8 years.
The Acidity of Precipitation
pH in precipitation has decreased considerably at almost every station
in Europe. Fiaure 5 gives an example of the monthly values from Tystofte
12
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Tystofte
1955
1960
1965
1970
Figure 5. Monthly pH-values from the station Tystofte in Denmark
1955 - 1971. The station is still in operation but data are
not yet available.
in Denmark. The Figure illustrates three phenomena rather common in this
type of data:
1. The occasional occurrence of higher to much higher
pH values in relation to the general bulk of data. They appear
mostly in summer time and are likely to be due to local
deposition of alkaline dust. The lack of co-variance between
nearby stations excludes a more largescale effect. In general,
summer values are higher. This can be seen for the years 1958,
59, 60, 64, 65, 66 and 69.
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2. A long-term periodicity seems to appear at this station.
The length of the period is approximately 12 years. The cor-
relation with nearby stations is fairly low, which indicates that
the variation at Tystofte is local or less than the grid of the
network. For other stations a co-variance may appear for certain
years (cf Figure 6).
3. Generalized for the period, a negative trend takes
place at Tystofte. The pH-values drop from approximately 6 to
4. The same takes place at almost every place in Europe. Due
to long-term changes of local or regional character, the regression
line for pH with time is not so easy to determine.
The large variation in the data on a monthly basis is somewhat reduced
when yearly average values are computed. Examples from 6 stations are given
in Figure 6. The sequence of yearly data show, nevertheless, a large
variation, which makes it difficult to establish the trend for the period.
The solid regression line for each station was drawn (by eye) in 1970.
The additional data show that such trends are sometimes not always justified.
Th3 trend at Flahult and Plb'nninge is overestimated, at Smedby underestimated.
For the other stations the trends are fairly correct. A straight!ine
relationship means that the acidity has increased exponentially from 1955
to 1974. This is not likely to take place forever, and the most probable
trends are curves tending to a limit value of pH 4 or below. In all
circumstances the data in Figure 6 illustrates the difficulty to evaluate
the atmospheric chemical data. As yet there is, to my knowledge, no method
to reduce the variation between years. This ought to be possible, however,
since there must be some kind of physical reality in the co-variance
between stations. As shown, the curves for Kise and JU are very similar.
For long periods this is also the case for Flahult, Plonninge and Smedby.
The geographical distribution of the yearly mean pH-values of the
precipitation are shown in Figure 7. In 1956 a center of acidity (pH 5.0-
4.5) appeared over southeastern England, North of France and the Benelux
14
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pH
5fl
54-1
50-
46-
PH ,
58-
54-
50-
pH ,
58-
54-
50-
46-
4.2|
Robacksdalen
(Umei)
A •' \ , As
- V" V (Oslo)
1955 1960 1965 1970
1975
1955
1960
1965
1970
1975
Finure 6. Yearly averaae pH-values from 2 station in Norway and 4 in
Sweden. The straight trend lines were drawn in 1970. Note
the effect of additional data.
countries. Three years later the central area had become more acid (by
0.5 pH-units). The acidity is reduced outwards. The data from the U.S.S.R.
makes it possible to show that the European acidification was regional in
1959 and mainly isolated from the rest of the Continent. There is only a
tendency for an impact on northeastern European countries.
In 1961 and 1966 the situation worsened. In small areas (Benelux
countries) the yearly average pH-values were below pH 4 and areas inter-
fered by pH 4.5 - 4.0 were very large in 1966. The maps indicate that
the acidity was spreading to the east with the prevailing winds. On the
other hand, it can not be excluded that a second acidity center in U.S.S.R.
and the eastern European countries also has been enlarged and intensified,
forming a combined area of increased acidity with that of central Europe.
Maps have not been prepared for the years after 1968. This is partly
due to lack of data from some countries and partly to the fact that the
15
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pM»SO
45-iO
pH«<.o
Figure 1. pH-maps for Europe for four years. Isolines differ by .5 pH-
units. The maps are based on the yearly averaqe of 12 monthly
samples.
yearly averaqe pH-values are not properly related to the fallout of acids
or acid-forming substances. If, for example, the precipitation is sampled
for a whole year, the pH-values would be roughly .2 pH-units lower than
those given in Figure 6 and 7. This is a consequence of the fact that a
single monthly sample with a hiqh pH-value may increase the yearly averaqe
figure considerably but does not contribute to the acidity. The long-term
station records (cf Figure 6) indicate, however, that the acidity is still
increasing in Europe.
16
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There is no doubt that' sulfur forms a major but complex part of the
acidity of precipitation. At almost every station the sulfur content is
steadily increasing while pH is decreasing. Four examples are given in
Figure 8 to illustrate this relationship. A negative correlation is obvious,
but in the details the correlation is not too good. Chanqes in the fall-
out of bases like NHL, Ca, Mg and K as well as acids like N0_ will also
contribute to the acidity or the alkalinity of a sample. Actually, when
all ions are taken into account, the pH-values can be computed from the
balance of ions. This has been successfully done by the International
Meteorological Institute (Granat, 1972) and at Cornell (Coqbill et al_.,
1074).
P" "•
20
As IM
Smedby (Sw)
pH
6-
I'lonnm^c
pH S
6-
- 20
Aslcov (D)
1970
I9W
Figure 8. Sulfur and pH year by year at four stations in Scandinavia.
17
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When the fallout of sulfur is plotted year by year, the pattern is
very irregular. Some years the fallout is markedly higher in central
Europe and U.S.S.R.; other years this pattern disappears more or less.
The fallout of sulfur is obviously very sensitive to other factors than
the amount of emission. This has actually increased by 2 to 5% during
the last 15 years, but there is no smooth response in the fallout. There
are a multitude of causes to this. Some of these are listed below:
1. Photo-chemical oxidation of SCL with or without the influence
of ^
2. the concentration of ozone or
3. the occurrence of catalytic dust particles, or
4. the amount of NH, in the air, which dissolves in acid water
droplets. Furthermore,
5. the products formed will have different life times in the
atmosphere, and consequently the spreading effect will be
different. Unlike other elements,
6. the mixing of different air-masses may enhance or retard
reactions according to 3 and 4, and the spreading effect
according to 5. Finally,
7. sulfur takes part in exchange processes with soils, vege-
tation and surface waters. Small changes in this exchange
may influence strongly the fallout and consequently the
spreading of sulfur.
As yet, the effect of the complex sulfur chemistry has not been
worked out taking all these factors into account. Conflicting statements
are quite common. When the sulfur-acidity problem was first presented,
various objections were presented. Among others it was stated that the
lifetime of SCL was only a couple of hours. Consequently the emissions
of SCL from Great Britain or central Europe could not reach Scandinavia,
since sulfuric acid is very hygroscopic and falls out very rapidly after
its formation. Erronously evaluated cruise-data between Sweden and
18
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Great Britain was used to support this view. A second statement was that
SCL emitted in Great Britain is totally absorbed by the British grasslands.
However, the final sink for sulfur has not been presented. Vegetation and
soil humus is only a temporary sink for sulfur, and sulfur, absorbed by
plants, has to show up somewhere else, e.g., in surface waters. This is
not known to take place in Great Britain.
The emission of sulfur varies considerably between different countries
in Europe. The figures below are computed from the Swedish Case Study:
MA poMotion CLC.HUM national boanda^i^. T/ie impact en the environment
ofr -5tt£^uA in ail and pitc.ipi.tation, which was presented at the U.N.
Conference on the Human Environment in 1972.
Emissions of sulfur from some countries in Europe in 1965
The-figures are given in kg S/ha-year
Norway 2.5 France 20
Sweden 6.7 U.K. 131
Denmark 30 Holland 152
W. Germany 65
These figures show a very large variation among the countries. High
figures are likely to indicate that the atmospheric export is high, too.
This will especially be the case when a low-leveJ country is situated close
to a high-level country. A considerable import of sulfur to the north
Scandinavian countries from the United Kingdom and central Europe will thus
take place. This is evident from the sulfur content in Swedish rivers.
Only part of the discharge of sulfur can be accounted for by the emissions
within Sweden. Other countries like West Germany, North France and Holland
will just exchange their emission products. The geographical distribution
19
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of regions with intense emissions of sulfur along with meteorological
conditions forms a complicated pattern which not yet has been evaluated
quantitatively. An OECD-study has been undertaken in northern Europe in
an effort to tackle these interactions.
In 1961-62, I made a study of the chemistry of individual rain storms
and, simultaneously, determinations of the wind trajectories. Applied to
the present problem some results are given in Figure 9. The curves on
the maps show the trajectories three days prior to intense precipitation
in North and South Sweden respectively. They include all occasions with
precipitation during two months. The air masses are obviously passinq
different parts of emission areas in Europe, and will consequently be
oolluted with respect to that. When precipitation is formed, the different
pollutants will fall out. The least contaminated air (1) leads to a
precipitation with highest pH-value and lowest figures of S and Tot-N.
At trajectories 3 and 4 the pH drops and S and Tot-N increases substantially.
The situation for Cl is reversed, which is logical due to the ocean as
the main source for Cl. Dry and wet fallout along the trajectories reduces
the content.
The trajectories in Figure 9 show that the winds at precipitation
periods are mainly from west to south with respect to Scandinavia. At dry
conditions this is not equally well pronounced. Figure 10 shows (by
dots) the endpoints 24 and 60 hours respectively from a starting point
denoted by a circle. The spread of the endpoints is almost circular. The
mean position of all points (denoted by a cross) shows that a slight mean
wind to the east takes place. This is in accordance with the maps for
total-N and for pH.
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North Sweden
Si nit h Sweden
Trajectories at rain
1. N Great Britain and Denmark
2. S Cireat Britain and Benelux
3&4. Central and E Europe
PH
5.2
4.9
4.7
S
0.8
I.I
2.6
Tot-N
0.2
0.3
a?
Cl
2.3
I.I
0.6
Figure 9.
Wind trajectories to Sweden at all occasions of general pre-
cipitation. The chemistry of the precipitation reflects the
emission situation in Europe. Sampling period: October and
November 1962
21
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Figure 10. End points of trajectories at a height of 1.5 km from a point
(marked by a circle) in Northern Central Europe for (a) 24
hours and (b) 60 hours calculated every third day for a
period of about one year. Fifty percent of the points are
to be found within the circles which are centered around the
mean position of all points (marked with a cross).
From Swedens Case Study.
22
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The last two slides show clearly that the possibility for interactions
between different countries in Europe through the movements of air masses
is fairly large. There is no agreement, however, to the quantitative
aspects and neither to effects. As long as this state of matter persists,
reduction of emissions is not likely to be made.
Several studies have been made in Sweden and elsewhere to determine
the spreading distance from an isolated city or a point source like
smelters, power plants or paper mills. Theoretically this distance is
indefinite. However, measurements of this distance are limited not only
to the sensitivity of instruments but also due to the difficulties of
defining a proper base-line or background value. This is especially the
case for elements which take part in geochemical cycling, as, e.g., sulfur.
The high "noise level" and the more periodic fluctuations leads to an
underestimation of spreading distances. The spreading tail will thus be
incorporated in the background. At a place remote fror° cities and industries
many such tails may add up anonymously, leading to a change in the chemical
climate. This is what has taken place in Europe and large parts of
North America. A dome of smoke particles and chemical constituents covers
these areas more or less constantly. The local imrovements by means of
tall stacks has led to an extension of this pollution dome. Figure 11
shows what is visible in this respect: The emission of soot from cities
and industries along with soil erosion from deserted areas.
The amount of acids in a sample of precipitation is uniquely defined
by the pH-value at unbuffered conditions. When neak acids appear, the
buffer capacity of these acids has to be taken into account. Some reports
from the U.S. claim that weak acids make up a major part of the acids in
23
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Soot Clouds of the Northern
Hemisphere
Photo. NASA 1973.
Fiqure 11. The black parts on this satellite picture denote areas with
reduced air visibility due to soot and dust.
precipitation. This is not the case in Europe. Weak acids like acetic
acid or other organic acids or salts of iron or aluminum may appear
occasionally but their quantitative part in relation to the total acidity
is only a few percent. The differences between U.S. and Europe in this
respect can not be explained at present. Ongoing intercalibration
between laboratories in the U.S. may give the answer very soon.
24
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Another concept with respect to the amount of acids has been
proposed and even applied, e.g. in the Swedish Case Study. It has been
called "excess acids" and is computed by subtracting the sum of
alkalinity for those months with pH > 5.6 from the sum of acids in
monthly samples with pH < 5.6. pH 5.6 has been chosen because it is
the pH-value obtained when distilled water is in equilibrium with the
CCL of the air. However, local contamination by dust, lime, ashes,
etc. takes place at the sampling station now and then (cf. Figure 5)
and leads normally to high alkalinity values. Such a monthly value may
therefore be correct for the immediate place of the sampling station
but may be incorrect for a place 100 meters away. The almost non-
existent correlation between stations for months with high pH-values
shows that such values are not representative in a regional sense. The
concept of excess acids leads consequently to an underestimation of the
fallout of acids.
Another point has to be stressed. The concept of the atmospheric
acidity may be defined chemically in relation to pH 7.0 or pH 5.6 or any
other point of reference. Such definitions, however, do not account
for the acid (or alkaline) effect that will take place, when precipitation
is added to other systems like soils, waters, vegetation, metals,
buildings, etc. As an example, a precipitation of pH 6.0 is chemically
slightly acid with respect to the neutral point of pH 7.0, fairly acid
with respect to ocean water of pH 7.8 or a wall of concrete of pH 8.5,
but it is alkaline with respect to a farm soil of pH 5.0. The low
pH-values at present in part of the U.S. and Europe (pH 4.0 - 4.5) are
still alkaline with respect to a peat bog with pH-values normally below
25
-------
4.0. Consequently, the acidity of precipitation and the amount of acids
in precipitation can only be defined in relation to something outside the
sample, and these quantities must therefore be given different values.
Only changes (in time or between places) are chemically definable from
intrinsic properties of the precipitation sample(s).
Changes in the Chemistry of Surface Waters
Changes in the acidity of air (dry fallout) and precipitation (wet
fallout) will have an impact on natural reservoirs as well as technical
systems. Through the water quality network and adjacent studies of soils
and surface waters a substantial amount of data have now accumulated to
establish various effects of this impact. For the most part, my original
presentation of these effects in 1968 have been verified by subsequent
data (Oden, 1968).
Figure 12 shows the monthly pH-values from three of the fifteen
sampling stations, which started in 1965. Their locations are given in
Figure 2. These records (along with the other 12) show (1) random
variations, (2) seasonal variations, (3) yearly variations, (4) time
trends and (5) a singular discontinuity. Some of these points will be
discussed in some detail.
A seasonal reduction of the pH-values takes place almost every
spring. The effect is most pronounced in small watersheds, at high altitudes
and in northern latitudes. In complicated river basins with a mixture of
waters of different age and chemical quality at the point of sampling,
this effect vanishes almost totally. Sometimes the drop in pH occurred
simultaneously with other changes like increasing color and the content
of oxidizable material as measured by the consumption o^ KMnO. (cf. Figure 13).
26
-------
1973
Figure 12. pH-records from 3 sampling stations of the Swedish water
quality network during 1965 to 1974. A pH refers to the
discontinuity denoted by an arrow in the beginning of
1970.
27
-------
50 -j mg/l
25 -
0 -ti
A PH
7.0 -
1968
1969
1970
Figure 13. Records of pH and the consumption of XMnO, from the sampling
station at river Ljusnan. The station is localized in
Figure 2.
This effect proved to be related to the melting of the snow cover. In the
first phase of the melting period most ions separate from the package of
snow. The meltwater is salty and much more acid than the bulk of snow and
will drain on top or in the upper layer of the otherwise frozen soil. A
rapid flow to the tributaries of the river gives rise to drastic changes
in the chemistry of the river water. Such changes may have a profound
influence on fish life as a kind of shock effect.
During the second phase of the snow meltina almost distilled water
infiltrates into the soil. If the ground water reservoir is filled at that
time the equivalent amount of more or less alkaline ground water is
extruded into the surface waters. pH is then rapidly restored.
28
-------
This model has been applied and verified by others in Scandinavia. The
effect on thermally stratified lakes has been shown to be of special interest.
The discontinuity in the pH-records in 1970, denoted by an arrow in
Figure 12, is also related to snow. The storage of snow was especially
large during the winter of 1969-70. The soil, however, was almost
unfrozen that winter and at snow melting most of the meltwater infiltrated
into the soil leading to the alkaline ground water effect discussed
previously. The A pH at the point of discontinuity is well related to
the amount of calcareous materials in soils and the bedrock within the
different river basins. Where calcareous materials do not exist the
pH-discontinuity is not noticable.
The pH-trends in all Swedish rivers investigated since 1965 (some
from 1963) are all negative. The regression lines seem to be straight
within the investigated period, and the discontinuity in 1970 apparently
does not lead to a change in the slope. If the slopes are extended to
pH 5.5, which is supposed to be a biologically critical pH-value, a
"lifetime of health" is obtained. On the average, 600/ of the investigated
rivers in Sweden will reach this critical point in 40 years, and as much
as 90% in 80 years. Each discontinuity will ext°nd these ages by 4 years
on the average. The frequency of such jumps, however, is not known.
In 1965 and 1970 we made a synoptic water quality study of
Scandinavian surface waters by roughly a 1000-point network. pH showed
up to form several regions with lower pH-values than the surrounding
areas. Such regions were southwestern Norway, the westerly part of
Sweden and some areas in the interior of middle and southern Sweden. The
reduction in pH in these regions is most likely a consequence of the
29
-------
increasing acidity in Europe along with soil conditions of low buffering
or neutralizing capacity.
Natural waters are normally buffered by soluble substances (PO.,
organic acids, amino acids etc.), colloidal organic matter (humus, seston)
and bicarbonate. A set of buffering curves from stations of the Swedish
water quality network is shown in Figure 14. The rivers SE, SF and SL
have obviously low buffering capacity and are consequently sensitive to
additions of acids. The shape of the curves makes it clear that all waters
are very pH-sensitive in the range of pH 4.5 - 6.5. Small additions of
acids at a pH of 6.5 may thus cause a rapid drop to pH 4.5. Above pH 6.5
the waters may be highly pH-stable due to bicarbonate (cf. SA and SB in
Figure 14).
At present the content of bicarbonate steadily decreases in Swedish
lakes and rivers. As such this has no direct biological consequences
but it indicates the chemical changes that occur. The waters, however,
tend to be more liable to rapid pH-changes, which is known to interfere
with fish life. The reduction of bicarbonate is due to the addition of
strong acids within the watershed area. The only acid of any importance
in this respect is sulfuric acid or its salt ammonium sulfate. The ratio
HC03/SO. is consequently a sensitive index (besides pH) of the continuing
acidification of natural waters. Four examples are given in Figure 15.
All rivers show a continuous decrease in this ratio. The slope is steepest
in rivers in the south and west of Sweden, which is in accordance with the
atmospheric fallout of acids. When this ratio is zero, bicarbonate has
disappeared. pH is then around 5.5, i.e., the pH-value previously
discussed as a critical one. When the slopes are extended to its zero
30
-------
lm.e. Base/I
10 pH
Figure 14. Bufferinq curves of waters from the Swedish water quality
network. The dot on each curve denotes the pH-value at
the time of samplinq.
-------
Indalsalven
HCO,,
V SO,
I •>-
1.0-
0.5-
0-'
Atran
HC03
T» 0
y SO4 Botorpsstrom men
1965-1974
Figure 15. The ratio of bicarbonate to sulfate on an equivalent basis
for four rivers of the Swedish water quality network. For
location of the sampling stations, see Figure 2.
value, figures for the lifetime of a healthy state of the rivers will be
obtained. Such computations give figures which are almost identical with
those based on the pH-trends (cf. Figure 12).
The chemical changes in Swedish river waters, illutrated by our data
from 1965 to 1974, started, of course, much earlier. This can be
illustrated by the relationship between Ca and HCO., from three different
periods. Each line in Figure 16 represents the regression line for a
large number of data from lakes and rivers. As can be seen there is a
gradual increase in the slope with time. The discharge of a given amount
of Ca will consequently take place with successively lesser and lesser
amounts of HCO.,. This is only possible if HCO is exchanged by another
J 3
32
-------
kg/ha
/
5O-
40-
3O -
20-
10-
South Sweden
and
industrial pollution
O O
O
Figure 16. The discharge of Ca and HCO~ by Swedish rivers at different
time intervals. The circles refer to rivers in South Sweden
and those polluted by calcium sulfate.
anion, e.g., like sulfate. The figures below show that the discharge of
sulfate by Swedish rivers actually has increased considerably since the
beginninq of this century.
I S C H A R G E
OF
S 0 — S , KG/HA' YEAR
REGION
;|ORTH SWEDEN ,
CENTRAL SWEDEN ,
SOUTH SWEDEN ,
SKANE - BLEKINGE
> 65°N
60°N - 65°N
< 60°N
1909 - 1923
2.3
4,4
10.3
12.5
1965 - 1972
6.3
9.1
21.0
31.0
33
-------
The discharges of sulfate were more than twice as high at present.
When only the anthropogenic part of sulfur is taken into account the
increase is three to five times over the period. In the southeast part
of Sweden (Skcine - Blekinge) the increase of anthropogenic sulfur is
about 20 kg S/ha-year within a period of 50 years. In the form of
sulfuric acid, the total load for the period has thus amounted to 1500
kq per ha.
The Impact of Acids on Soils-
The chemical conditions in lakes and rivers reflect in a more or
less complicated way reactions and chanqes in the soil system and
occasionally in the bedrock. When the lake area is small in relation to
the drainage area, neither sink mechanisms in the bottom sediments nor
the effect of precipitation on top of the surface water has to be taken
into account. In Sweden 80 to 95% of the water in lakes and rivers is
actually a mixture of soil water and qroundwater.
As a model, the relationship between precipitation (and dry fallout),
infiltration, groundwater runoff, surface water runof^ and the mixinq of
different water categories is illustrated in Figure 17. At the soil
surface and the zone of infiltration a multitude of reactions will take
place.
When strong acids or acid-forming substances are brought to the soil
the following reactions will take place. An increase of the acidity of
the soil solution will be a primary effect (1). However small, this will
lead to an exchange of adsorbed cations on the soil colloids (2). The
desorbed ions will be leached out of the soil (3) and the degree of base
saturation will be reduced (4). A more acid and a less nutritive state
34
-------
Acid precipitation and the soil water reservoir
wet and dry fallout
4, 4, 4,
pH s4.0
infiltration
pH 3.5-6.0
surface water run off
pH 3.5-6.0
mixing in lake*
pH < 7.5
ground water run off
pH s7.5
Figure 17. Part of the hydroloaical cycle related to soils and surface
waters.
will have an effect on plant growth (5) and will change the composition
of the plant community in the long run (6). Such bioloqical changes are
likely to m've a feedback effect of increased acidification (7).
Furthermore, the rate of mineralization of litter and humus will be
retarded (8). Until a new equilibrium is obtained the cycling of nutrients
in the ecosystem will be retarded, too (9). Some of these effects will
to some extent be counterbalanced by increased weathering (10) of the
soil minerals. On the other hand, when a soil type with accumulation
horizons is affected, large amounts of ions, i.e. heavy metals, may start
to dissolve (11). Processes of soil formation will be enhanced and less
productive soil types will be formed (12).
Some of the 12 items above have been verified in our studies. Others
have been formulated as postulates since they are derived from common
knowledge in Soil Science or Soil Biology. It is only a matter of time
and intensity before all effects are verified. Some examples are given
below.
35
-------
In 1970 we made a soil survey of forest soils in Sweden and Norway.
Sites similar with respect to soil type and vegetation (185 places) were
selected and samples were taken down to a soil depth o^ 50 cm. The maps
for pH and the degree of base saturation are shown in Figure 18.
r~n
10 10 20 ~ 20 ,
Figure 18. pH and the degree of base saturation at the upper 5 cm of
podsolized forest soils in Scandinavia. From Sweden's
Case Study.
There is a large continuous zone on the southwestern part of Scan-
dinavia with lowest figures both in pH and in the degree of base
saturation. This part is also closest (with respect to wind conditions)
to the Center of acidity in Europe. A small area of similar soil changes
occurs west of Stockholm. At a place within that area alum shale has
36
-------
been burned for decades, giving rise to large emissions of SCL. The
effects on the soils, however, is only local.
The atmospheric acidity has for the most been related only to
mineral acids like sulfuric acid, hydrochloric acid and nitric acid.
The irreversible adsorption by the plants of any kind of cation will also
give rise to increased acidity in soils and waters. Anions, on the
other hand, will cause the reverse effect, i.e. making the systems more
alkaline. Since the net effect of the ionic uptake by plants acidifies
the systems, I have called this effect "biological acidification."
When this concept is applied, for instance, to a peat bog, its pH-value
around 4 can be adequately explained solely by processes of bioloqical
acidification. There is no room for humic acids or the like from an
explanatory point of view.
NH^-salts form a major part in the processes of biological
acidification. As shown in Figure 3, this compound increases with
time in the precipitation leading to increased acidification of soils
and waters. At present, however, we do not know the exact fiqure for
the total load (wet or dry) of acids or acid-forming substances. Our
best judgment related to the southwestern part of Scandinavia amounts to
2
100 mil 1iequivalents/m per year or 1000 equivalents per ha per year.
This is equal to 50 kg concentrated sulfuric acid. This fiqure is
approximately 3 times hiqher than the figure used in the Swedish Case
Study.
When the figure above is applied to a normal podzol in Scandinavia
without calcareous materials in the subsoil we can compute the time
necessary to desorb all the cations down to half a meter. The computation
37
-------
gives a formal figure, which is always the case when residence time or
turn over time are computed. We arrive at a figure of 150 years. Long
before that time biological effects will have shown up.
As indicated by Figure 18 the soils in southwestern Scandinavia
are already considerably depleted of cations. In comparison with a
normal podzol these soils have lost between 55 to 70% of their original
content of cations. The higher figure refers to the subsoil. Most of
these losses, but not all,has to be attributed to changes of the chemical
climate during the last 100 years.
Due to the very high heterogeneity in soil characteristics it is
very difficult to determine chemical changes in soils over a short period
of time. Data from the Swedish water quality network, however, gives
some of the answers. Figure 19 gives an example from river Atran
(cf. Figure 2). SO.-S has increased by more than 5 kg in 10 years. When
the reduction of the agricultural use of fertilizer -S during the last
decade is accounted for, this increase is actually 10% larger. HCO~
decreases by almost 20 kg (cf. Figure 15) and the total amount of cations
has increased by approximately 360 E/ha. In the form of CaC03 the last
figure equals 18 kg/ha. pH is reduced by 0.2 units. The following
identity can now be formulated, where X denotes processes of biological
acidification.
391 + X = 360 -t 283; X = 252 E/ha
The reason for this identity is qiven by Figure 19. Biolonical
acidification has increased by 252 E/ha during the last 10 years. The
absolute value is not known at present. Total acidification in this
part of Sweden has increased by 643 E/ha during the same time. Fifty-six
38
-------
20-
SO4-S
S/ha-year
1965
1970
Figure 19. Discharne of SO.-S, HCO, and the sum of cations (iM) from
the drainage arga of river Atran. Changes of these
quantities during the last ten years are given in
Equivalents/ha. X denotes the magnitude of processes of
biological acidification.
percent of this impact of acids is neutralized in the soil by ion exchanqe
and weathering. The remaining 44« suppresses the dissociation of
bicarbonate leading to diffuse emission of CCL to the atmosphere. When
HCCL is close to zero (pH of surface waters < 5.6) the effect of a given
amount of acids on the environment will consequently be almost doubled.
This "point of no return" has apparently been passed in certain areas in
Scandinavia. pH of about 4.5 are common in these areas where no local
sources are known.
In order to document that the soil effects measured in southwestern
Scandinavia are man-made (the opposite nas been argued) a similar study
around a copper smelter at Falun has been made. This smelter has been
39
-------
Soil horizon EU .
A
40-50 cm
Figure 20. Changes in pH and the degree of base saturation in the soi
around a copper smelter at Falun (150 km fJW of Stockholm).
The maps refer to a soil depth of 40 - 50 cm.
40
-------
Degree of
basesaturation %
Figure 20 (Continued)
41
-------
operating for about 500 years and the total emission of SOp amounts to some
5 million tons of SO^ over this period. Some results are shown in Figure
20.
pH has been considerably reduced in all soil horizons even down to a
depth of 40 - 50 cm. Close to Falun the acidity has increased more than
4 times with respect to a reference value of pH 5.0. In fact, the whole
area within the map is influenced by increased acidity at this depth. The
degree of base saturation is also considerably reduced. Far outside the
map the degree of base saturation is about 25%.
The conditions within the shaded areas at Falun are chemically very
similar to those in the southwest of Scandinavia with due regard to equal
conditions of bedrock and soil parent material. The growth of forest
trees has not yet been measured. According to growth results presented in
the Swedish Case Study a reduction of growth, however, is likely to have
taken place. The productivity of both pine and spruce has proved to be
much lower when the soil content of calcium is reduced.
*****
The framework and structure of the acidity problem, the effect on
natural and human systems and the dimension of the problem with respect
to time and space were outlined in 1968. The Swedish government acted
promptly but in vain. And we are still far from a qeneral agreement
between countries in Europe to debate emissions of acidifying compounds.
This is partly due to a variety of opposite positions (with respect to
this presentation) taken by scientific and advisory personnel since 1968.
Statements like "The idea of a reduced pH in precipitation in Europe is
only hypothetical, since pH can not be measured in such an unbuffered
solution" or "Increased fallout of acids is beneficial for pine trees
42
-------
because they like acid conditions" seem not to be very constructive in
order to tackle this large-scale problem.
Part of this paper was presented as a plenary lecture at the 19th
Congress of the International Association of Limnology in Winnipeg in
1974 (Oden & Ahl: Man-made Changes of the Scandinavian Environment).
The Congress adopted the following resolution:
"Whereas, the increased introduction of man-made pollutants to the
atmosphere is seriously contaminating the earth's airsheds, often remote
from local sources, and
Whereas, the fallout of these materials is contributing to
acidification and other pollution of lakes, rivers, air) groundwaters
of large geographic regions, and,
Whereas, the recently observed, and projected chanqes in acidity
of waters represent a serious stress for natural aquatic ecosystems,
Therefore, this Congress deplores such degradation of aquatic
ecosystems, and urges government, scientists, engineers, and laymen
everywhere to investigate thoroughly the ecological magnitude of these
changes, and to undertake prompt and ecologically sound remedial
action."
It is my sincere hope that the members of this New York State
Conference will adopt these statements and transfer them to legislative
actions.
Part of the work presented in this paper has been sponsored from
time to time by the Research Council of the Swedish Environmental
Protection Board. The Swedish Case Study was supported by the Government.
43
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REFERENCES CITED
Cogbill, C.V. and G.E. Likens. 1974. Precipitation in the Northeastern
United States. Water Resources Research 10(6) 1133-1137.
Granat, L. 1972. On the Relationship Between pH and the Chemical
Composition in Atmospheric Precipitation. Tellus V. 24, pp. 550-
560.
Oden, S. 1968. The Acidification of Air and Precipitation and its
Consequences on the Natural Environment. Swedish Nat. Sci. Res.
Council, Ecology Committee, Bull. No. 1. Translation Consultants,
Ltd., Arlington, Va. No. Tr-1172.
44
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ACID PRECIPITATION:
OUR UNDERSTANDING OF THE PHENOMENON
Gene E. Likens*
Introduction
Our awareness and understanding of the phenomenon of acid precipitation
in the United States is just beginning. It is believed that acid precip-
itation in the industralized northern Temperate Zone is caused by the
oxidation and hydrolysis of gases (S07 and NO ) in the atmosphere generated
£. A
from the combustion of fossil fuels; only recently has the regional nature
of the problem become apparent (Likens, 1972; Likens, e_t a_]_., 1972; Likens
and Bormann, 1974; Cogbill and Likens, 1974). Likewise, ecological and
economic concerns have been recently formulated, but are largely unquantified
in the United States. Thus we must start with a series of fundamental
questions which prescribe the scope and foci of the problem.
Central Questions
The first question is: What would be the pH in an unpolluted area on
a long term basis? That is a very difficult question to answer because there
are no historical records of actual pH measurements of precipitation in the
U.S. prior to about 1939 (Cogbill, 1975). So, as a point of reference the
pH value, 5.6, has been taken as the lowest pH that could be produced by
carbonic acid if pure water were in equilibrium with atmospheric carbon
dioxide (Barrett and Brodin, 1955). Dr. Oden would use a pH value appreciably
*Professor, Ecology and Systematics, Cornell University, Ithaca, New York,
14853.
45
-------
higher than this (this symposium). In the northeastern United States we
find that rain and snow are currently at pH's much lower than 5.6, i.e.
precipitation is several hundred times more acidic than would be expected.
Values of pH < 3.0 have been measured for individual rainstorms in the
northeastern U.S. (Likens and Bormann, 1974). These lowered pH's are
brought about by the presence of strong acids, sulfuric and nitric, in
rain and snow (Galloway, et_ al_., 1975).
A monthly record of precipitation pH for central New York and the
White Mountain region of New Hampshire is shown in Figure 1. These data
show that pH values throughout the year are appreciably lower than would
be expected on the basis of a carbon dioxide equilibrium alone. They
also show that over this large area of the northeastern United States the
pH values are essentially the same. Summer pH values are generally lower
than winter values; that is, summer rains are more acidic than winter
snows. The average pH weighted for volume of precipitation over the course
of a year then, at all of these locations (Figure 1), is about pH 4.
The next question is: What is the source of the acidity in precip-
itation? We've looked at this rather carefully in our studies of precipitation
chemistry at Cornell. There are various potential sources of protons in
precipitation (Table 1). In the left-hand column of Table 1 are the strong
proton sources—the strong acids, sulfuric, nitric and hydrochloric - that
dissociate fully in water to produce free protons. In the right-hand
column are sources of bound protons in precipitation: carbonic acid, a
generalized organic acid, clay particles, ammonium, aluminum and ferric
hydroxide. These latter substances are all sources that could contribute
to the total acidity of a solution, i.e., the acidity determined by
46
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Hubbard Brook, N.H
Aurora, N.Y.
Ithaca.N.Y.
~> •
June
July
Aug.
Sept. Oct.
1970
Nov.
Dec.
Jan.
Feb.
Mar.
Apr.
1971
May
June July
Figure 1. The pH of precipitation in the Finger Lakes reqion of New York State and at the Hubbard
Brook Experimental Forest in New Hampshire (from Likens, et al., 1972).
-------
Table 1. Proton Sources in Precipitation (from Galloway, et al., 1975).
Strong Proton Sources
Bound Proton Sources
¥°4
HNO,
HC1
RCOOH
Clay
NH/
A13+
Fe(OH)
titration with a base, but they provide bound protons rather than free
protons in solution at pH's less than 5.0. The free protons can be measured
with a pH electrode, bound protons cannot. We have evaluated the sources
and relative proportions of free and bound protons in samples of precip-
itation from central New York, from the Hubbard Brook Experimental Forest
in New Hampshire, and from the Adirondack region of New York (in association
with Carl Schofield).
An example of the relative contribution of free and bound protons from
each of the potential proton sources in a precipitation sample at pH 4.0
is given in Table 2. The concentration of each potential proton donor is
typical of precipitation samples in central New York (Ithaca), in the White
Mountains of New Hampshire or in the Adirondack Mountains of New York. At
a pH of 4 there would be no contribution to the free (measurable) protons
in solution from carbonic acid. One of the analytical difficulties when
48
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Table 2. Sources of Acidity in Precipitation* in the
Northeastern United States (from Galloway, et al_., 1975).
Concentration in
Precipitation
(mg/O
Contribution to
Free Acidity at
pH 4.0 (ueq/a)
Contribution to
Total Acidity in
a Titration to
pH 9.0 (ueq/£)
¥°3
Clay
NH.
4
Al
Fe
Mn
RCOOH
HNO~tr
3
V°4ft
0.62
5
0.350
0.050
0.040
0.005
1.1
2.1
2.9
0
0
0
0
0
0
6
34t+
60ft
**
5***
19f
5
1
0.1
17
34
61Q
* Sample collected 27 February 1975 at Ithaca, New York.
**
was removed from the system by N~ purging.
If the
was not
removed and the system was at equilibrium with the atmosphere, there
would have been 5000 peq/s. contribution to total acidity and no contribution
to free acidity in a titration to pH 9.
***This assumes that all of the particulate material is montmorillonite clay;
most likely the contribution to total acidity is an order of magnitude
less than 5 ueq/£ because of minerals other than montmorillonite, which
have a much lower exchange capacity.
f This assumes that all of the NH4 is converted to NH3 which is subsequently
removed by the N? purge. The most likely value is between 7 and 19 yeq/&.
The contribution to the free acidity is determined by a stoichiometric
formation process in which a sea-salt anionic component is subtracted from
the total anions (Cogbill and Likens, 1974).
At pH 4.0, 1.5% of the total sulfate is present as HS04~; thus total acidity
for sulfate is greater than the free acidity.
49
tt
-------
determining the total titratable acidity of a precipitation sample is -
that great care must be taken to titrate the sample under nitrogen gas
or some other inert atmosphere. If this were not done and the titration
were conducted from..say, pH 4 to pH 9, carbon dioxide from the atmosphere
would be stirred into the sample and thus add a large artifact to the
total acidity value. Unfortunately, this mistake is frequently made in
analyzing precipitation samples.
Clay particles at a concentration of 5 mg/liter contribute no free
protons to a precipitation sample at a pH of 4. Likewise, aluminum at
a concentration of 0.05 mg/£ contributes no measurable protons; iron at
a concentration of 0.04 mg/fc and maganese at a concentration of 0.005
contribute none; and ammonium at a concentration of 0.35 mg/£ contributes
no free protons to a solution when the pH is 4. Thus none of these
substances would contribute to the free acidity (ambient pH), but all of
the substances could contribute to the total acidity of a sample of
precipitation (Table 2).
We also have looked for some 33 different organic acids in precipitation,
since it has been suggested that they could contribute significantly to
the measurable acidity. We have found only one (isocitric acid), and it
contributed 6 yeq/2. of the free protons at a pH of 4 (Table 2). Because
a solution at pH 4 would contain 100 ueq/£, the organic acid would contribute
only 6% of the total -free protons in solution. The remainder of the free
protons (94/o) are contributed by sulfuric and nitric acids. In all cases
where we have looked carefully at the precipitation chemistry, the con-
tribution of free protons in solution from the bound proton sources is very
minor—less than 15%. The majority of the protons are contributed by strong
50
-------
acids, sulfuric and nitric. Thus precipitation is currently a strong
acid solution in the rural and semi-urban areas of northeastern United
States.
The next question is: How long has the precipitation been dominated
by strong acids? I've tried to look carefully at the historical record
in this regard. It's very difficult, however, because I have been unable
to find any actual pH data for precipitation samples prior to 1939, and
no synoptic data prior to 1962 for the United States (cf. Cogbill, 1975).
The earliest known measurement of precipitation pH in the U.S. was done
on a single rainstorm in August of 1939 at Brook!in, Maine; a pH value
of 5.9 was obtained (H. G. Houghton, personal communication). Then in
August of 1949 at Washington, D. C. Landsberg (1954) measured the pH of
eight individual raindrops with a microelectrode of a Beckman pH meter.
The mean value of these eight drops was pH 4.2. In 1952-53 Landsberg
(1954) measured the pH of individual raindrops during a large number of
storms near Boston, Massachusetts, with pHydrion paper. The mean value
was 4. These latter data from Landsberg (1952-53) have been taken to
show that precipitation in the eastern U.S. was markedly acidic by
1952-53 (Cogbill, 1975). However, experiments with pHydrion paper in our
laboratory have shown that the hydrogen ion content of individual raindrops
may be overestimated by 5 to 6 orders of magnitude with this indicator
paper. Conversations with the manufacturer (Micro Essential Laboratory,
Brooklyn, N.Y.) have confirmed this, and in fact several milliliters of
precipitation solution are required to make reliable determinations with
the pHydrion paper. Thus measurement of individual raindrop pH by this
method would be very misleading.
51
-------
Obviously then, not enough actual data exist prior to 1962 to indicate
area!, annual or seasonal patterns of precipitation pH for the United
States. However, there exists detailed chemistry for some precipitation
samples taken prior to 1950, particularly in Tennessee (1917-1922), in
central New York State (1919-1928) and in Virginia (1923-1928). Also we
found that it is possible to accurately "predict" or calculate the pH of
precipitation if one knows the chemistry of a sample (Cogbill and Likens,
1974).
The stoichiometric relationship for calculating hydrogen ion con-
centrations is based on Granat (1972) and is shown in Figure 2. All
cations and all anions in solution are summed and proportioned into their
component parts. One component is attributable to a source in the sea
(we call these sea-salt components) and contributes a certain amount of
neutralized salts to the total solution. Some of the remaining acid-
forming sulfate, nitrate and chloride anions, commonly referred to as
excess ions, are neutralized by ammonium, calcium, magnesium, sodium and
potassium ions in solution. There remain then an amount of sulfate,
nitrate and chloride ions in solution that is balanced by hydrogen ion.
We have found in present-day samples that we are able to predict this
hydrogen ion concentration quite accurately from determinations of total
chemistry (Cogbill and Likens, 1974). Predictions actually agree with
measured values to within a few hundredths of a pH unit in almost every
case we've analyzed from a variety of locations (including New York State,
New Hampshire, Tennessee and Virginia). In practice it is very difficult
to make a pH measurement in the field reproducable to better than 0.1 of
a pH unit, so our calculated pH is an entirely satisfactory way of
determining pH.
52
-------
Anions Cations
I 1
J
i
i
Acid
w Formii
o
X— 1
I/)
to
o
UJ 1
'
>
Neutral!;
r \
J
ig
red
^
Sea Salt
L
S04= N°3
i i
1
I
i
___«>!
«
H+
NH* CA**,
MG*4, K*
_CA^M6*V_.
NA*
Figure 2.
Theoretical ionic relationship between major chemical components
in precipitation (from Cogbill and Likens, 1974).
53
-------
Cogbill (1975) used this procedure to evaluate some of the early
samples (prior to 1930) from Tennessee, central New York State, and
Virginia. His results indicated that precipitation chemistry during this
period was characterized by high ionic concentrations, but low acidity
relative to present-day samples. Predicted pH's for these early samples
ranged between 6.5 and 7.4. There also were some alkalinity determinations
done on these samples using methyl orange and cochineal solutions; these
results indicated that the samples obtained before 1930 were at pH's in
excess of 6.9 (Cogbill, 1975).
However, since at least 1955-56, precipitation in the northeastern
United States has been much more acidic (pH < 5.6). Using chemical data
from Junge (1958) and Junge and Werby (1958) for 1955-56, we calculated
the distribution of pH in the eastern U.S. (Figure 3). Based upon these
data much of the eastern U.S., particularly the northeastern U.S., was
being subjected to acidic precipitation by 1955-56. Magnesium values
were not reported for these precipitation samples, but the maximum error
generated by this would be less than 5%
The same procedure was applied to chemical data for the U.S. from
the National Center for Atmospheric Research during the period 1960-66
(Lodge, e_t al_., 1968), for North Carolina and Virginia during 1962-63
(Gambell and Fisher, 1966), and for New England and New York during 1965-66
(Pearson and Fisher, 1971). The pattern of precipitation pH that was
predicted from this analysis for 1965-66 is shown in Figure 4.
It should be noted that the pH 5.6 isoline moved westward and south-
westward from 1955-56 to 1965-66, and that there was an intensification of
acidity of precipitation in the northeastern region. The National Center
54
-------
1955- 1956
5.42
>6.CO
Miles
0 50 100 200 300
I.I I I
0 62 124 186
km
Fiqure 3. Predicted pH of precipitation over the eastern U.S. durinn the
period 1955-56 (from Cogbill and Likens, 1974).
55
-------
1965- 1966
Mi les
0 100 300
62 186
km
Figure 4. Predicted pH of precipitation over the eastern U.S. during the
period 1965-66 (From Cogbill and Likens, 1974).
56
-------
for Atmospheric Research also determined pH at 28 stations in the
coterminous U.S. during 1964-66, but these data have never been fully
published (Lazrus, e_t al_. , 1974). Values as low as pH 2.1 were measured
during this period. Actual measured values for June, 1966, are
representative of the pattern of pH values for the entire U.S. during
1964-66 and are shown in Figure 5. I think these data are of particular
interest because I know of no other maps available for the entire U.S.
which give any idea of the distribution of measured pH of precipitation
over the course of a year. A study done by high school students during
a two-week period in March, 1973, sponsored by "Current Science", also
provided some data for the U.S. (Strong, 1974).
Figure 5. The pH of precipitation over the United States during June,
1966. Data courtesy of the National Center for Atmospheric
Research (A. L. Lazarus, personal communication).
57
-------
89
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uaaq aABq 01 saBaddB a^aqi uiBSy -(g a^nBij) 'S'n ujaissa aqi uo^
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aq I,UOM a^aqi Hse9-iB auiLOSi,, aqi j.o AUB ULqiLM isqi A~[duu iou
pLnoqs siqi -(f aunbLj) 99-g96L -lOj. uuaiiBd Hd pa^OLpaud aqi A"L90j.u
BIBP avDN asaqi 'UOLiBiLdpa^d A"q pa6uaABDS isnp j.o asnaoaq
B A"iq6iq aq ABLU 'S'O uaa^saM aqi ui uoiiBiidpaad UOLSBDOO
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-------
1972- 1973
7.60
5.60
.52
Miles
0 100 300
62
186
km
Figure 6. Observed pH of precipitation over the eastern U.S. during
the period 1972-73 (from Cogbin, 1975).
59
-------
monthly interval. Considering the problems of contamination and biogeo-
chemical transformations that may occur in a reservoir of a precipitation
collector in the field, our experiences have shown that sampling intervals
of not longer than a week are highly desirable, if not necessary, to
obtain accurate data on precipitation chemistry. In areas where dry fallout
is more prevalent, sampling of individual precipitation events may be
the only alternative to obtain reliable precipitation chemistry. At Hubbard
Brook, dry deposition is a small proportion of the total wet and dry
deposition.
Sulfate and hydrogen ions dominate the precipitation falling on the
forested watersheds at Hubbard Brook (Likens, e_t al_., 1976). On an
equivalent basis S04~ is 2.5 times more common than the next most abundant
anion, N03", and hydrogen ion is 5.9 times more prevalent than the next
most abundant cation, NH^ . On a long-term basis, the total negative
equivalent value is 94.9% of the total positive value and cation and anion
sums are not statistically different (Table 3). The determination of
hydrogen ion is probably our principal analytical error in determining an
equivalent balance. Hydrogen ion concentration was estimated from measure-
ments of pH, and errors of the order of + 0.05 pH unit would be sufficient
to explain the discrepancy in the cation-anion balance. However, consid-
ering that these long-term averages include the various sampling ana
analytical errors over 8- to 11-year span, the agreement is quite good.
Thus we can say with confidence that precipitation at Hubbard Brook
can be characterized as a contaminated solution of sulfuric and nitric
acid at a pH of about 4.1. The average annual weighted pH during the
period of 1964-65 to 1973-74 ranged between 4.03 and 4.21 (Figure 7).
60
-------
Table 3. Weighted annual mean concentration in bulk precipitation for
the Hubbard Brook Experimental Forest (from Likens, e_t aj_. 1975).
Substance
•
Ca++
Mg++
K+
Na+
NH4+
H+
S04=
N03-
Cl"
PO ~~
A
Lt^f\
n wVj f^
TOTAL
{mg/0
0.16
0.04
0.07
0.12
0.22a
0.073ab
2.9a
1.47a
0.47C
0.008d
5.54
Precipitation
1963 - 1974
(peqA)
7.98
3.29
1.79
5.22
12.2
72.4
60.3
23.7
13.3
0.25
(+J102.9
(-) 97.7
al964-1974
"'calculated from pH measurements on weekly samples
'1965-1974
J1972-1974
^calculated from H - HCO-," equilibrium
61
-------
-3.95
IS72
Figure 7. Annual weighted mean concentrations in precipitation for the
Hubbard Brook Experimental Forest during 1955-1974. The values
for 1955-56 were extrapolated from isopleth maps given by
Junge (1958) and Junqe and Werby (1958). Note that the
ordinate has been compressed (from Likens, et a!., 1975).
62
-------
Rarely do pH values approach 5.0 and in the past year they have not
exceeded 5.0 for any collection period. The lowest value reported for
a single storm at Hubbard Brook was pH 3.0. Such precipitation is
decidedly abnormal chemically, as discussed above. Furthermore, much
of the dissolved and particulate matter normally present in precipitation
would tend to increase the pH by several units. In other words,
precipitation at Hubbard Brook has a hydrogen ion concentration 50 to
500 times greater than expected.
There was a downward trend in annual pH values between 1964-65 and
1970-71 followed by an upward trend until 1973-74. If we had sampled
only during this period, we could have made a case of the fact that
the pH was dropping dramatically, and precipitation was becoming more
acidic. If we had started our studies in 1970, we could have made the
opposite case, i.e. that the pH was increasing and precipitation was
becoming much more alkaline. This points up the pitfalls of short-term
data. No overall trend in annual pH values was statistically significant
during the period 1964-1974 (Figure 7).
Likewise, concentrations of S0.~ and NH. vary from year to year,
but there were no statistically significant trends for the decade. In
contrast, annual NO.," concentrations currently are about 2.3-fold greater
than they were in 1955-56 or in 1964-65 (Figure 7). The sum of all
cations, except hydrogen ion (EM -H ), decreased from 51 ueq/£ in 1964-65
to 25 yeq/i in 1973-74, which represented a 55% reduction in this
component of precipitation during the period.
Even though the annual hydrogen ion concentrations were variable, the
annual input (concentrations times volume) in precipitation increased by
63
-------
1.4-fold during the period from 1964-65 to 1973-74 (Figure 8). Thus
by 1973-74, more than 1.1 equivalents x 10 H /ha-yr were being deposited
on forested ecosystems at Hubbard Brook in precipitation. This increased
input in hydrogen ion was in sharp contrast to the annual input of all
other ions except nitrate (Table 4). Based upon a regression analysis,
annual nitrate input increased by 2.3-fold during the decade. There
was no significant increase in annual sulfate input during the period.
The increased annual input of hydrogen ion is partially explained
by the significant increase in amount of annual precipitation during the
10-year period (Table 4), but data for individual years show that factors
other than increased precipitation are important (Figure 8). In fact,
hydrogen ion input is only weakly related to annual precipitation input
(Figure 9). Thus other factors also are operative in regulating the annual
input of hydrogen ion, and consequently annual weighted concentrations
(pH) alone do not accurately reflect trends in total annual input.
The input of nitrate and sulfate also are directly related to the
amount of annual precipitation (Figure 10). There is more variability
in the sulfate relationship to precipitation than for nitrate, and in
fact without the very wet and very dry years the relationship would not
be meaningful (Figure 10). In contrast to hydrogen ion, sulfate and
nitrate, the input of all cations (summed) except hydrogen ion is not
related to amount of-annual precipitation (Figure 9).
Surprisingly, the input of hydrogen ion was not significantly
related to sulfate input over the 10-year period (Figure 11). Even
though sulfuric acid is the dominant acid in precipitation at Hubbard
Brook (Table 3), the annual input of sulfate did not increase significantly
64
-------
1.2r
_c o
^ x
c c
4) QJ
O) —
£ 5
-o 5
-?" v
X oi
c
o
.
o o
0) *~
£ x
— m
a a>
3 t:
c —
0.9
0.8
0.7
0.6
1.8
1.6
U
1.2
1.0
0.8
0
1964-65 66-67
68-69
Year
70-71
72-73
Figure 8. Annual hydrogen ion and water input in precipitation for the
Hubbard Brook Experimental Forest. The regression line for
hydrogen ion is Y = 0.003X + 0.819 where Y is the H+ input in
equivalents x 10^ per hectare and X is the year. The
significant correlation coefficient is 0.74. Note that the
ordinate has been compressed (from Likens, et al., 1975).
65
-------
Table 4. Regression analysis of annual precipitation input on year
for the Hubbard Brook Experimental Forest (from Likens, et al. 1975)
Substance
Ca++
Mg++
K+
Na+
NH/
H+
so4=
N03"
Cl"
Water
Slope
-0.174**
-0.046*
-0.126*
-0.003
0.110
0.033*
0.279
0.388**
0.300
4.96*
Correlation
Coefficient
-0.83
-0.66
-0.66
-0.02
0.57
0.74
0.32
0.78
0.22
0.72
Time Period
1963-74
1963-74
1963-74
1963-74
1964-74
1964-74
1964-74
1964-74
1967-74
1963-74
* probability of a larger F-value < 0.05.
**probability of a larger F-value < 0.01.
66
-------
CO
O
c.
3
o-
0)
13
a.
c
a
3
C
C
1.2
1.0
0.8
0.6
0.4
0.
EM+-H*
o
o
.0 O
J I I 1 1 1 1 1
20 40 60 80 100 120 140 160 180 200
Annual Precipitation (cm/ha)
Fiqure 9. Relationship between annual input of hydronen ion and all
other cations except hydrogen ion (iM+-H+), and precipitation
input for the Hubbard Brook Experimental Forest during
1964-1974. The regression line is Y = 0.004X + 0.437,
where Y is the annual hydroqen ion input in equivalents
X 1Q3 per hectare and X is the annual precipitation in cm
per hectare. The correlation coefficient is 0.67 and the
probability of a larger F-value is < 0.05. The slope of
the regression line for EM+-H"1" is not significantly different
from zero (from Likens, et al., 1975).
67
-------
-3
T
o
en
CD
~~J O fD
en -s 3-
-S 3 -••
ft> —'••-£>
—' rt- 3-
cu -s —i
c-t- O) «<
-J. rt
O fD l/i
~1 ' f~i
O ft) 3
O U3 —*•
fD ~5 -h
-h fD -••
~h (/J O
—i. 1/1 Ol
n ->• 3
-•• o n-
fD 3
3 x—
rt- —' O
- _.. o
3 -S
o n> -s
o>
O) TO
3 03
cr
o fD
-h rt-
-T3 fD
-S fD
fD 3
O
T3 3
-•• 3
Annual Input (equivalents x 10 /ha)
O -••
3 3
• -o
— ft) O
-h -s 3
-s <<
o o
33-0
_,. ft)
I— 'J3 -h
fD "< O
3 -••
1/1 VI fD
^ -i. 3
U3 rt
|fD 3 -
-h O
—• O CO
. 01 _•
rt
o>
3
0.
3-0
ro -h
(/) (/)
c: c
— • — '
-h -h
cu cu
rt r+
ft) fD
-S O
ro -s
D
-5 3
n> — '•
l/l r-v
to -S
ft)
•• 3
3 CL
fD
O
ro
o
CJ
o
r-
<=>
ui
o
en
p
'-o
p
CD
O
UD
O ^-«
Q OD
— o
•- o
•o
o
D
g S
I §
-------
c S
*
O) C
O 0)
1.2
1.0
0.8
0.6
">, > 0.4
0.2
a-
0)
i i i '
_1 L
0 0.2 OX 0.6 0.8 1.0
Sulfate Input (equivalents x 103/ha-yr)
Figure 11. Relationship between the annual hydrogen ion input and the
annual sulfate input during the period 1964-65 to 1973-74.
The slope of a regression line fitted to these data was not
significantly different from zero (from Likens, et al.,
1975).
69
-------
during the period, whereas the annual input of hydrogen ion did (Table 4).
In contrast, the annual hydrogen ion input is highly correlated with
the annual nitrate input during the past decade at Hubbard Brook (Figure
12). The 1:1 relationship between annual inputs of hydrogen ion and
nitrate is a powerful argument that nitric acid is the crucial variable
in explaining the increased input of hydrogen ion during the past 10 years.
Precipitation chemistry has changed both qualitatively and quanti-
tatively at Hubbard Brook during the past decade. Absolute concentrations
have varied (Figure 7) and relative proportions of the component chemicals
have changed. Based on a stoichiometric formation process in which the
sea-salt component is subtracted from the total anions in precipitation
(Cogbill and Likens, 1974), the sulfate contribution to acidity dropped
from 83% to 66% and nitrate increased from 15% to 30% from 1964-65 to
1973-74. Annual inputs reflect these changes in complex ways. In an
attempt to resolve the relative importance of the various factors controlling
the annual hydrogen ion inputs, a step-wise, multiple regression analysis
was performed to relate the annual hydrogen ion input to a variety of
independent variables. An analysis of five independent variables indicated
that 86% of the variability in annual hydrogen ion input during the decade
was related to annual nitrate input. Six percent of the variability was
due to annual sulfate input, 5% to the input of the sum of all cations
minus hydrogen ion, 2% to the year and less than 0.01% to the annual
amount of precipitation.
I conclude from these studies that although sulfuric acid dominates
the precipitation at Hubbard Brook and has for a decade, the increased
annual input of hydrogen ion during the past ten years apparently has been
due to an increase in the nitric acid input to this rural forested ecosystem.
70
-------
CO
O
o-
0)
a.
1.2r
1.0
• 0.9
a
0.8
0.7
0.1
0.2
0.3
0.4
0.5
0.6
NO" Input ( equivalents x 103/ha-yr)
Figure 12. Relationship between the annual hydrogen ion input and the
annual nitrate input during the period 1964-65 to 1973-74.
The regression line: Y = 1.07X + 0.631, where Y is annual
input of hydrogen ion in equivalents x 103/ha-yr and X is
annual nitrate input in equivalents x 103/ha-yr, is highly
significant (correlation coefficient of 0.84, and probability
of larger F-value is < 0.01) (from Likens, et aj_., 1975).
71
-------
General Remarks
These are the kinds of changes that we have seen in precipitation
chemistry in a rural area of New England. There are now studies underway
on the effects of these acidic inputs on the growth of forests, on
streams and lakes, and on soils in the area. The geochemical effects
at present seem to be minimal in the Hubbard Brook area (Johnson, et al.
1972), but we don't know whether there may have been a greater effect
some 20-35 years ago as the precipitation became more acid. The
biological effects on the forest may be significant (Whittaker, et a 1.
1974) but these data are difficult to interpret and will require further
analysis and study (Cogbill, 1975). Dr. Carl Schofield will say more
about the important ecological effects of acid precipitation on fresh
water ecosystems.
I would like to add one final point. The acid precipitation problem
has been shifted from a localized problem to a regionalized one, where
acid precipitation is seen in widespread areas remote from the sources of
S0? and NO . Acid precipitation is not a new phenomenon—acid rain and
snow have been known and studied for at least 75 years, but the studies
were on localized problems—localized around cities, near smelters, or
close to fossil-fueled power plants. Recently this problem has been
exacerbated by the increased combustion of fossil fuels and by the increased
height of smokestacks, which tend to spread the pollutants over greater
distances. The "philosophy" guiding the disposal of these combustion gases
apparently has been similar to the old adage, "out of sight, out of mind."
Much of our "waste treatment" follows this same kind of thinking. I
would respond with another old adage: "everything that goes up must come
72
-------
down." Apparently wastes being deposited on rural New York and New
England as acid precipitation were "disposed of" great distances upwind.
73
-------
REFERENCES CITED
Barrett, E. and G. Brodin. 1955. The acidity of Scandinavian precipitation.
Tellus 7:251-257.
Cogbill, C. V. 1975. Acid precipitation and forest growth in the north-
eastern United States. M.S. Thesis, Cornell University.
Cogbill, C. V. and G. E. Likens. 1974. Acid precipitation in the northeastern
United States. Water Resour. Res. 10(6):1133-1137.
Galloway, J. N., G. E. Likens and E. S. Edgerton. 1975. Hydrogen ion
speciation in the acid precipitation of the northeastern United
States. First International Symp. on Acid Precipitation, May,
1975, Columbus, Ohio. (In press).
Gambell, A. W. and D. W. Fisher. 1966. Chemical composition of rainfall
in eastern North Carolina and southern Virginia. Geol. Survey Water
Supply Paper 1535-K. 41 pp.
Johnson, N: M., R. C. Reynolds and G. E. Likens. 1972. Atmospheric sulfur:
its effect on the chemical weathering of New England. Science
177(4048): 514-516.
Junge, C. E. 1958. The distribution of ammonia and nitrate in rain water
over the United States. Trans. Am. Geophys. Union 39:241-248.
Junge, C. E. and R. T. Werby. 1958. The concentration of chloride, sodium,
potassium, calcium and sulfate in rain water over the United States.
J. Meteorol. 15:417-425.
Landsberg, H. 1954. Some observations of the pH of precipitation elements.
Arch. Meterorol. Geophys. Bioklim. Ser. A. 7:219-226.
Lazrus, A. L., B. W. Gandrud and J. P. Lodge, Jr. 1974. Acidity of U.S.
precipitation. Paper presented at AGU Symposium, April 1974,
Washington, D. C.
Likens, G. E. 1972. The chemistry of precipitation in the central Finger
Lakes region. Water Resour. Mar. Sci. Center Tech. Rept. 50, 62 pp.
Likens, G. E. and F. H. Bormann. 1974. Acid rain: a serious regional
environmental problem. Science 184(4142):1176-1179.
Likens, G. E., F. H. Bormann and N. M. Johnson. 1972. Acid rain. Environ-
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likens, G. E., F. H. Bormann, R. S. Pierce, J. S. Eaton and N. M. Johnson.
1976. Temporal variation and pattern in the biogeochemistry of a
northern hardwood forest ecosystem. (In Prep.)
74
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Likens, G. E., F. H. Bormann, J. S. Eaton, R. S. Pierce and N. M. Johnson.
1975. Hydrogen ion input to the Hubbard Brook Experimental Forest,
New Hampshire during the last decade. First Internat. Symp. on
Acid Precipitation, May 1975, Columbus, Ohio. (In Press).
Lodge, 0. P., Jr., K. C. Hill, J. B. Pate, E. Lorange, W. Basbergill,
A. L. Lazrus and G. S. Swanson. 1968. Chemistry of the United
States precipitation. Final report on the national precipitation
sampling network. Laboratory of Atmospheric Sciences, National
Center for Atmospheric Res., Boulder, Colorado. 66 pp.
Pearson, F. J., Jr. and D. W. Fisher. 1971. Chemical composition of
atmospheric precipitation in the northeastern United States. Geol.
Surv. Supply Paper 1535. 23 pp.
Strong, C. L. 1974. The amateur scientist. Sci. Amer. 230(6):126-127.
Whittaker, R. H., F. H. Bormann, G. E. Likens and T. G. Siccama. 1974.
The Hubbard Brook ecosystem study: forest biomass and production.
Ecol. Mongr. 44(2):233-254.
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ACID PRECIPITATION: OUR UNDERSTANDING OF THE ECOLOGICAL EFFECTS
Carl L. Schofield*
I would like to preface my comments concerning our understanding
of the ecological effects of acid precipitation by briefly quoting the
introductory section of a document entitled "Recommendations to the
Workshop Panels of the First International Symposium on Acid Precipitation
in the Forest Ecosystem."
"Scientists from many countries have convened at this
symposium to define the present status of knowledge concerning
changes in the chemical climate of the earth, especially
those that cause acidification of rain, snow, soil and fresh
water systems. These changes are inducing significant
alterations in aquatic and terrestrial ecosystems. There is
substantial evidence that these changes in the chemical
climate are due in large part to increased emissions of man-
made pollutants, but the extent and magnitude of their effects
are not adequately understood. An integrated and international
program of research is needed to deal with these problems.
Therefore this symposium authorizes a set of workshop panels
to formulate recommendations for research, to evaluate exchange
processes between the atmosphere and natural reservoirs, and
exchange reactions within these reservoirs especially those
detrimental to life processes."
It goes on to list some fairly specific recommendations which I
won't consider here. These panels were convened following the Ohio
Symposium, and their recommendations will be published in the proceedings
of the 1st International Symposium on Acid Precipitation and the Forest
Ecosystem. The statements I've read indicate that significant alterations
have been recognized in aquatic and terrestrial ecosystems. These
alterations appear to have been induced by changes in atmospheric
*Senior Research Associate, Department of Natural Resources, Cornell
University, Ithaca, New York 14853.
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chemistry. However, the extent and magnitude of these effects are not
adequately understood, nor have they been thoroughly assessed.
The Ohio Symposium attempted to assess the effects of acid precip-
itation on aquatic systems, forest soils and specifically, forest
vegetation. Not considered were agricultural systems and the structural
*
damage to man-made components that Professor Oden mentioned yesterday.
Problems related to forest soils and vegetation are not within my area
of expertise, and I would not presume to evaluate them to any great
extent at this time. I will highlight only a few of the significant
problems relative to terrestrial systems and leave further discussion,
additions, or clarification to others in this audience more knowledgeable
than I in this field.
Acute effects of acid precipitation on soils and vegetation have
been clearly identified only under extreme conditions, either experi-
mentally induced or in situations very close to sources of heavy air
pollution (e.g., Sudbury, Ontario). The relative significance of strong
acids and associated heavy metals found in heavily polluted areas, has
not been clearly established in terms of toxic effects on plants and
soil organisms. The most serious consequence of regional acidification
at currently observed levels may be the increased rate of leaching of
major elements and trace metals from forest soils and vegetation. This
is true both for the forest ecosystem and for the aquatic systems
receiving these effluents. The increased mobility of certain elements
such as aluminum, manganese and zinc, particularly at low pH, could be
viewed as a very serious consequence in terms of their toxic properties
at low pH; and for aluminum especially because of its role as a proton
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donor and acid buffer. Sandy soils, low in exchange capacity, appear
to be potentially the most sensitive to strong acid atmospheric deposition.
Very acid podzols or highly calcareous soils represent extremes in
soil pH; however, both types possess higher exchange capacity and
relatively greater resistance to change in pH or free hydrogen acidity.
The change in pH or increase in free hydrogen ion concentration may not
be the most significant factor involved in the soil acidification
process. Increased mobility of aluminum and iron, which may have direct
toxic effects on plants, can additionally interfere in processes such
as phosphorus transport in germinating seedlings.
Being more familiar with aquatic systems and since they also appear
to be most sensitive to a phenomenon such as acid precipitation, I will
confine the remaining discussion to problems associated with atmospheric
inputs to dilute lakes and streams. One point I would like to make
absolutely clear. Precipitation currently falling on remote areas in
the northeastern United States, Scandinavia, and parts of Europe, is an
acutely toxic medium to fish and other aquatic organisms. The average
concentrations of strong acids and heavy metals found in precipitation
from these areas greatlv exceeds the known tolerance levels of many
organisms inhabiting the lakes and streams in these regions. Obviously
aquatic systems cannot be likened to "rain barrels" and certainly the
soils and vegetation of the drainage basin will modify the chemical
composition of lake and stream waters to varying degrees. The major
questions are then: to what extent, how, and under what conditions are
the toxic components of acid precipitation reduced or increased in
natural systems and what are the responses of the biota to these modi-
fications?
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The significance of atmospheric contributions to the chemistry of
dilute surface waters was first demonstrated quite clearly by the work
of Gorham (1958). He compared the major ion content of waters in the
English lake district to precipitation inputs and found that lakes
lying in areas of hard, resistant bedrock received most of their major
ion supply from precipitation and were correspondingly very dilute. It
is also quite evident that this atmospheric-lake water chemistry
relationship is dynamic and anthropogenic induced changes in precipitation
chemistry will be reflected in the chemical and biological composition
of dilute surface waters in sensitive regions. "Sensitive regions" are
defined as North Temperate Zone geologic provinces, characterized by
igneous or metamorphic bedrock, shallow soils, and the presence of acid
precipitation. Extensive areas in Sweden and Norway, localized sections
of the Canadian Shield in Ontario, and the western slopes of the
Adirondack Mountains of New York State represent regions where lake and
stream acidification has resulted in severe ecological damage (Wright,
1975; Beamish, 1975; Schofield, 1975).
At the risk of being somewhat provincial, I'd like to consider one
of these areas, specifically the Adirondacks, with which I am most
familiar, and utilize this as an example of how atmospheric inputs
relate to surface chemistry in dilute waters.
The Adirondack Mountains are located in the northern part of New
York State. A substantial lake district, consisting of about 2,300
lakes, is distributed throughout the region in a northeast - southwest
orientation. The areas of highest elevation are in the east central
and south to west quadrant of the Adirondack province. Geologically,
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the area belongs to one of the oldest mountain formations known in
eastern North America, and the bedrock consists principally of
anorthosite and granitic gneisses. The soils are predominately acid
podzols, but regional differences in soil pH and calcium content reflect
differences in development that have occurred since the last glaciation,
primarily in response to climatic variations in the region. The
atmospheric flow affecting this particular area comes principally from
the land mass of the North American continent. The high mountains in
the southern and western areas intercept moisture laden air masses,
resulting in orographic precipitation effects. Precipitation is heavy
in the high mountain areas and much of this occurs as snow in the
winter months. A large proportion of the runoff occurs as snowmelt
in the spring. The precipitation falling on this area is quite acid
and exhibits pH values as low as 3.5 in the summer; however, the weighted
annual averages more closely approximate pH 4.2. There are strong
acids present in this precipitation and they constitute 80 - 90% of
the total titratable acidity.
As expected, based on these rather severe climatic conditions and
edaphic conditions, the lakes and the streams of the region are very
poorly buffered and usually of low pH. The lakes and streams exhibiting
the highest levels of acidity are found in areas of high elevation,
principally those lying at elevations greater than 2,000 feet. Most of
the alkalinity, or capacity to neutralize acids in lakes at lower
elevations is due to bicarbonate derived from weathering of silicate
minerals, rather than crystalline limestones which are rare in this
region. The soils developed from glacial deposits at the lower elevations
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significantly increase the major cation (Ca, Mg, Na, K) supply in the
drainage systems of these lakes and it is principally the higher calcium
concentrations which offset excess atmospheric sulfate inputs. In
contrast, sulfate replaces bicarbonate as the major anion in the high
elevation lakes, because of the presence of strongly leached, base
deficient soils in the comparatively small drainage basins. Strong
hydrogen acidity develops in the presence of excess sulfate and buffering
by aquo-metal ions such as aluminum and iron become significant. The
development of low pH (4-5) conditions in these high elevation lakes due
to the presence of strong acids (principally H^SO.), is clearly
dependent on the balance between cation supply from the drainage basin
and the loading of excess acid forming anions in precipitation. The
extreme sensitivity of these poorly buffered, high elevation lakes to
acid loading from atmospheric sources can be demonstrated by modeling
the mass balance of major ion inputs. For example, an increase of 0.5
ppm SO. in Adirondack precipitation (annual weighted average concentration)
over current levels, would be sufficient to increase the hydrogen ion
concentration in a 2,000 ft. elevation lake having zero acid neutralizing
capacity (pH ^ 5.6) one order of magnitude (^ pH 4.6).
The marked temporal fluctuations in pH that occur in streams and
lakes with relatively short retention times exemplify the significance of
acid precipitation effects on a short term basis. Increases in hydrogen
ion concentration of 10 to 100 fold have been observed in Adirondack
streams and lakes during periods of snowmelt. Fish mortality is known
to occur during these events; however, the extent and significance of this
phenomenon to the eventual extinction of populations is as yet unknown.
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Hultberg (1975) observed sharp pH drops under ice cover in Swedish lakes
during spring thaws and attributed this to ion separation of pollutants
stored in the snowpack. Wright (op cit) described the same phenomenon
in Norwegian streams, where massive fish kills have been observed during
spring snowmelt periods.
Long term changes are somewhat more difficult to assess due to the
general lack of historical data. Looking at some of the changes that
occur within fish populations as they tend to go to extinction, I think
we can see a common factor that is involved both in the Adirondack lakes
and those that have been studied in Sweden and Norway. Low levels of
acidity (e.g. pH 4.5-5.0), which are tolerated by some species of adult
fish, do interfere with reproductive processes to the extent that
recruitment failure often results. The size and age structure of a fish
population may shift to one where only a few large and old individuals
remain prior to extinction. This same effect has been noted in acidified
Canadian lakes by Beamish (1975) in the vicinity of Sudbury, Ontario.
Different causes have been ascribed to this reproductive failure
and perhaps some or all may be involved. It was suggested that there
is a failure in ovarian maturation in females due to acid stress. It
has also been indicated that there are loss of fry, particularly for
spring spawning species that are subjected to low pH values for the
snowmelt. What is actually involved in each case we do not as yet know.
We also see somewhat more subtle changes in some lakes that have become
marginally acid. For example, increased growth rates have been observed
in populations where decreased recruitment has lowered population
densities to the extent that food availability for the remaining
individuals is increased.
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There are factors other than hydrogen ion concentration that are
important in determining survival or relative survival of fish in aquatic
systems. One is the total ionic strength of the system or concentration
of other ions. High calcium and sodium concentrations ameliorate the
effects of hydrogen acidity. In contrast, synergistic components such
as zinc and copper may greatly accelerate death times in acid waters.
It was pointed out yesterday that there were increases in the lead
concentration of the Greenland snowpack since the Industrial Revolution.
This increased atmospheric loading of metals has been noted in biological
systems as well. Heavy metals concentrations found in samples of mosses
collected across Sweden during the period 1850 to the present indicate
a trend of increasing concentration. Atmospheric deposition of zinc and
lead is high in the northeastern area of the United States. The point
is that just considering possible contribution of metals from this
source alone to aquatic systems, the resulting concentrations are very
close to those known to produce chronic or even acute toxic effects in
some species of fish. In combination with the problem of acid waters
the situation could become particularly severe.
I think there are other unknowns involved concerning the process of
acidification in relation to the role of heavy metals, their sources, and
synergistic effects. We have to be concerned with the relative significance
of acute versus chronic responses in biological systems. The chronic
responses are often very difficult to identify, particularly those that
relate to changes in growth or reproductive failure as examples that I've
mentioned. We know very little about the relative sensitivity of various
species at different trophic levels in the ecosystem to acidification processes
83
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and even less of community and ecosystem responses. Grahn (1975) described
some rather marked feedback mechanisms that may occur in some lake
systems when acidification occurs. This involves the incursion of
normally terrestrial plant species such as Sphagnum into the littoral
zone of the lake and an acceleration of the acidification process. Other
changes occur at the decomposer level and involve shifts from bacterial
to predominately fungal decomposition. There are many other facets of
the acidification problem that need further investigation, particularly
in relation to the processes and rates of change involved. At the
present time our understanding of the ecological effects of lake and
stream acidification is primarily descriptive in nature. Intensive
lake studies and carefully designed monitoring programs will be required
to enhance our understanding of the acidification process.
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QUESTIONS AND ANSWERS
Q: Based on your analysis of changes in fish populations in the Adirondack
lakes, what is your assessment of the overall changes in the
Adirondacks in terms of fish populations?
A: The only place we've seen very marked changes have been these rather
remote, high elevation lakes. We don't have a complete assessment
for the whole Adirondacks, and what we're trying to do now is
evaluate the changes observed within this group of high elevation
lakes, which is a statistically definable system.
Q: What is the number of lakes affected?
A: Based on the survey data that I am now completing, something on the
order of 50 - 60% of the total number of lakes over 2,000 feet in
elevation are devoid of fish life.
Q: That's with no fish populations now, but where fish were known to be
present previously?
A: No, we don't have that kind of information. I'd say that in about
15 to 20 lakes we know positively that there were fish populations
present at times in the past and that currently there are none.
There are many more acid lakes where there are no data relative
to fish populations.
Q: Just thinking about the acidity and the snowmelt contribution, why
don't the lakes remain acid during the summer?
A: Some of them do. Lakes with small watershed to surface area tend
to maintain low pH throughout the year. In smaller systems, where
the retention time is less, there's a subsequent input of ground-
water and surface runoff that has significant acid neutralizing
capacity and the pH tends to increase during the summer.
Q: If precipitation acidity should decrease, would water quality in
affected lakes improve?
A: Well, I think we can get an approximation from seasonal observations
in systems with short hydraulic retention times. The question
whether responses would be forthcoming in the long term will depend
on what is happening in the soils, about which we know very little.
If there are no significant changes in soil chemistry, then one
should expect improvement in lake water quality over a relatively
short period of time, corresponding to the flushing time of the
system.
Q: You cited data by Gorham, and you mentioned that that data has an
atmospheric relationship to aquatic life. I really don't understand
that statement.
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A: What I've been trying to say primarily is that the acids found in
some of these lakes are strong acids, predominately sulfuric, and
they seem to originate from atmospheric sources. Excess anions
in the system originate primarily from atmospheric sources.
Q: You really don't relate those acids (sulfuric and nitric) in water
to ambient measurements in the air?
A: No, not to gaseous precursors, only to acid end products dissolved
in precipitation.
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REFERENCES CITED
Beamish, R.J. 1975. Effects of acid precipitation on Canadian lakes.
Proc. 1st Intl. Symp. on Acid Precip. and the Forest Ecosystems
(In Press).
Gorham, E. 1958. The influence and importance of daily weather
conditions in the supply of chloride, sulphate, and other ions
to fresh waters from atmospheric precipitation. Phil. Trans.
Royal Soc. London Series B. 241 (679):147-178.
Grahn, 0. 1975. Macrophyte succession in Swedish lakes caused by
deposition of airborne acid substances. Proc. 1st Intl. Symp.
Acid Precip. and Forest Ecosystem (In Press).
Hultberg, H. 1975. Thermally stratified acid water in late winter -
a key factor inducing self-accelerating processes which increase
acidification. Proc. 1st Intl. Symp. Acid Precip. and Forest
Ecosystem (In Press).
Schofield, C. L. 1975. Lake acidification in the Adirondack Mountains
of New York: Causes and consequences. 1st Intl. Symp. on Acid
Precip. and Forest Ecosystem (In Press).
Wright, R.F., Dale, T., Gjessing, E.T., Hendrey, G.R., Henricksen, R.,
Johannessen, M., and J.P. Maniz. 1975. Impact of acid precipitation
on freshwater ecosystems in Norway. 1st Intl. Symp. Acid Precip.
and Forest Ecosystem (In Press).
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HEALTH EFFECTS OF ACID AEROSOLS
Jean G. French*
The major research effort in the study of adverse health effects
of air pollutants in the past has centered around the primary pollutant
such as sulfur dioxide (SO,,) and nitrogen dioxide (NO,.,). We have now
come to realize that the transformation products may be more toxic than
the primary pollutants themselves.
Recent reports emanatinq from epidemioloqic studies carried out
as part of the Community Health and Environmental Surveillance System
of EPA indicates the levels of suspended sulfates associated with certain
adverse health effects were lower than the levels of SO- and total
suspended particulates (TSP) associated with the same health effect.
A study of asthmatics carried out in the Metropolitan New York
area showed that when temperatures rose to 30-50°F dose related increments
in asthma attacks were associated with increments in total suspended
particulates and suspended sulfates but not sulfur dioxide. The estimated
3
threshold level for total suspended particulates was 56 uq/m while that
for suspended sulfates was 12 ug/m (Finklea, Farmer e_t aj_. , 1974). In
a similar study of asthmatics in the Salt Lake Basin, the highest morbidity
rates were associated with elevated suspended sulfate levels (Finklea,
Calafiore et al., 1974).
*Epidemiologist, Human Studies Laboratory, National Environmental Research
Center, United States Environmental Research Center, Research Triangle
Park, North Carolina 27711.
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In a study of cardiopulmonary patients in the New York Metropolitan
area, the strongest and most consistent pollutant effects were associated
with suspended sulfates for aggravation of such symptoms as shortness of
breath, cough and increased production of phlegm. There was evidence
3
that annual average suspended sulfate levels of 10-12 ug/m was accompanied
by morbidity excess which averaged about 6% when temperatures were 30 to
50°F and 30% when temperatures were greater than 50°F (Goldberg, et al.,
1974).
Since these initial studies, subsequent studies of asthmatics in
the New York-New Jersey Metropolitan area and in two communities in the
southeast support previous findings that exposure to elevated levels of
suspended sulfates when accompanied by elevated temperatures may contribute
to excess risk of asthmatic attacks. These later studies also showed
that suspended nitrates may have a similar effect and in some instances
the combination of elevated suspended nitrates and suspended sulfates
seemed to exert a greater effect than either pollutant alone (French,
et a]_.).
The associations found in these epidemiologic studies by themselves
are insufficient to incriminate suspended sulfates and suspended nitrates
as causative agents of certain adverse health effects. However, when
these findings are coupled with those from experimental animal studies,
the observations appear more than spurious and a rationale for the patho-
genesis of the observed effect begins to emerge.
Studies conducted by Amdur (1969) using the guinea pig as the primary
model, have shown that in terms of comparative toxicity sulfuric acid
and some metallic sulfate compounds such as zinc ammonium sulfate are
89
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more potent irritants than sulfur dioxide gas. Amdur found that if the
particle size of zinc ammonium sulfate and sulfuric acid is essentially
equivalent, sulfuric acid has the greater irritant potency. However
if the zinc ammonium sulfate is present in a finer state of dispersion
than the sulfuric acid, the zinc ammonium sulfate is the more irritating.
As a gas, 1 ppm of sulfur dioxide produces an increase of about 15" in
flow resistance. If through reaction in the atmosphere this amount of
sulfur was converted to 0.7 u sulfuric acid, it would produce a resistance
increase of about 60 percent, a four-fold increase in irritant response.
If the equivalent of S02 were converted in the atmosphere to zinc ammonium
sulfate of 0.3 u, the response would be about a 300 percent increase in
resistance, a twenty-fold increment.
In other studies Amdur took both water soluble and insoluble non-
irritating aerosols and combined them with sulfur dioxide gas. These
experiments resulted in an increase in the irritating potential of the
water soluble aerosols combined with SO^ but no discernible change in the
insoluble aerosols combined with S0?. Amdur concluded from these studies
that the major mechanism underlying the potentiation of the irritating
effect of particulate material on the response to sulfur dioxide is
solubility of sulfur dioxide in a droplet and subsequent catalytic
oxidation to sulfuric acid (Amdur, et_ aj_., 1968).
Recent experiments by Frank and McJilton (1973) confirm Amdur's
findings and indicate the importance of relative humidity in the response
of animals to the S0?/sodium chloride atmosphere. Guinea pigs were
exposed for one hour intervals to atmospheres of 40% and 80% relative
humidity. Significant changes in pulmonary flow resistance occurred only
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in the combined SO^/sodium chloride aerosol atmosphere at high relative
humidity.
In a study conducted by Hazelton Laboratory (Alarie, et_ al_., 1973)
groups of cynomolgus monkeys were exposed for 78 continuous weeks to
sulfuric acid mist at concentrations varying from 0.38 to 4.79 mq/cu m
and particle size varying from submicronic to 4u mass median diameter
(MMD). The results signified concentrations of 2.43 and 4.79 mg/cu m
with particles of 3.60 u and .73 u MMD respectively, were sufficient to
produce definite deleterious effects on pulmonary structures and deteri-
oration in pulmonary function. Microscopic changes observed were principally
characterized by focal epithelial hyperplasia and focal thickening of
the bronchiolar walls.
Fairchild, ejb a]_. (1975) recently reported that a short-term high
concentration exposure to H^SO. aerosol (15 mg/m , 3.2 micrometers count
median diameter [CMD]) slowed the rate of clearance of non-viable, radio-
labelled streptococci from the nose and lung of mice. Inhalation of a
small aerosol particle (1.5 mg/m 0.6 micrometers CMD of H^SO.) did not
alter the clearance rate.
In another experiment Fairchild, Stultz, and Coffin found that a 60
3
minute exposure to 3020 ug/m H2S04 (1.8 urn CMD) resulted in a 60% greater
deposition of radiolabelled streptococcus aerosol in the naso-pharynx of
guinea pigs. When guinea pigs were exposed to 30 ug/m H?SO. (0.25 urn
CMD) there was a significant increase in deposition of the radiolabelled
streptococci in exposed vs controls but the site of increased deposition
shifted to the trachea. The author hypothesized that H2SO, inhalation may
induce increased air flow resistance which may result in altered patterns
of regional deposition of particles in the respiratory system.
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The aforementioned studies are not without certain limitations.
Most of the animal studies represent the work of one investigator using
the guinea pig as the principal model. A major limitation in the
Epidemiologic studies is the inability to characterize the measured
sulfate compounds in terms of their physical and chemical properties.
This poses a problem in trying to replicate the findings with respect
to suspended sulfates and nitrates since the chemical composition of
these pollutants may vary from one area to another and even within the
same community over time. It is also possible that sulfuric acid and
nitric acid in the ambient air are converted on the sampling filter and
then measured as sulfates and nitrates.
Presently special effort is being devoted by EPA Research and
Development to address the problems of measuring and characterizing acid
aerosols in ambient air.
I have attempted to describe the health effects which have been
identified with inhalation of certain acid aerosols in ambient air.
What has not been properly addressed is the interface of these acid
aerosols with water and soil and potential health problems from ingestion.
Very little research has been conducted in this area.
It is possible that acid rainfall from nitric acid might ultimately
lead to increased ingestion of nitrates. In the body nitrates may be
reduced to nitrites by. microbiological agents and cause problems such
as methemoglobinemia. The presence of precursor amines and nitrite in
the body also produces the potential for the formation of nitrosamines.
It has been suggested that the protonation of nitrous acid appears
necessary for initiating all nitrosation reactions and that carcinogenic
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N-nitrosocompounds in quantities considered to be potentially hazardous
cannot be produced unless the interaction of nitrite and amine occurs
in acidic medium (Ender, et^ aj_., 1964; Ender, ejt a]_., 1968; Crosby,
e_t al_., 1972). The nitrosamines are selectively hepatotoxic while the
nitrosamides damage the gastrointestinal tract, the blood forming organs
and the lymphoid system (Ridd, 1961).
The effect of acid rainfall on drinking waters throughout the United
States would be highly variable based upon the present pH of the water.
In some areas such as the southwest the drinking water is highly alkaline
and the acid rainfall would tend to neutralize the water. On the other
hand, in areas like New England where the water is already acid the
increased acidity of the water might well cause corrosion and the release
of metals into the drinking water which could cause some serious health
problems.
The interface of acid aerosols, in ambient air with soil and water
deserves much more study.
However, control measures directed toward controlling levels of acid
aerosols in ambient air to control the public health should have a profound
effect on controlling the problems of acid rainfall.
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REFERENCES CITED
Alarie, Yves, and W. Busey, A. Krumm, C. Erlich. Long-term Continuous
Exposure to Sulfuric Acid Mist in Cynomolgus Monkeys and Guinea
Pigs. Arch. Env. Health. Vol. 27, July 1973, pp. 16-24.
Amdur, M.O. and D. Undershell. "The Effect of Various Aerosols on the
Response of Guinea Pigs to Sulfur Dioxide." Arch. Env. Health
Vol. 16, July 1968, pp. 400-468.
Amdur, M.O. Toxicological Appraisal of Particulate Matter, Oxides of
Sulfur and Sulfuric Acid. Journal of Air Pollution Control
Association. September 1969, Vol. 19, No. 9, pp. 638-644.
Crosby, N.T., O.K. Foreman, J.T. Palframan, R. Sawyer. Nature
238-342 (1972).
Ender, F., G. Havre, A. Helgebostad, et al. Naturwissenschaften. 51:
637-638 (1964).
Ender, F. and L. Ceh. Food Cosmet. Toxicol. 6_: 549 (1968).
Fairchild, G.P., P. Kane, B. Adams, and D. Coffin. Sulfuric Acid Effect
on Clearance of Streptococci from the Respiratory Tract of Mice.
Accepted by the Archives of Environmental Health for publication,
January 1975.
Fairchild, G., S. Stultz, and D.L. Coffin. Sulfuric Acid Effect on the
Deposition of Radioactive Aerosol in the Respiratory Tract of
Guinea Pigs. Submitted to Journal of American Industrial Hygiene
Association.
Finklea, J.F., D.C. Calafiore, J.W. Southwick, C.J. Nelson, W. Riqgan,
C. Hayes and J. Bivens. Aggravation of Asthma by Air Pollutants:
1971 Salt Lake Basin Studies. Health Consequences of Sulfur Oxides:
A Report from CHESS. EPA No. 650/1-74-004, May 1974, U.S. EPA,
Research Triangle Park, North Carolina 27711.
Finklea, J.F., J.H. Farmer, J. Bivens, G.J. Love, D.C. Calafiore and
G.W. Sovocool. Aggravation of Asthma by Air Pollutants 1970-71
New York Studies. Health Consequences of Sulfur Oxides: A Report
from CHESS. EPA No. 650/1-74-004, May 1974, U.S. EPA, Research
Triangle Park, North Carolina 27711.
Frank, R., C. McJilton, R.
Synergistic Effect of
Science Vol. 182, pp.
Charlson. Role of Relative Humidity in the
a Sulfur Dioxide-Aerosol Mixture on the Lung.
503-504, November 2, 1973.
French, J.G., V. Hasselblad, R.J. Johnson. Aggravation of Asthma by Air
Pollutants: New York-New Jersey Metropolitan Communities 1971-72.
In-house technical report.
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Goldberg, H.E., A. Cohen, J.F. Finklea, J.H. Farmer, F.B. Benson and
G.J. Love. Frequency and Severity of Cardiopulmonary Symptoms in
Adult Panels 1970-71 New York Studies: Health Consequences of
Sulfur Oxides: A Report from CHESS. EPA No. 650/1-74-004, May
1974, U.S. EPA, Research Triangle Park, North Carolina 27711.
Ridd, J.H. Quart. Rev. Chem. Soc. 15, page 418 (1961).
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DISCUSSION SESSION ON THE PHENOMENON
John Hawley*, Discussion Leader
James Galloway**, Rapporteur
The fact that abnormally acidic precipitation is falling on most of
the eastern United States was well documented by Dr. Gene E. Likens of
Cornell University. He explained that acid precipitation is caused by
the strong acids, sulfuric and nitric, formed from the combustion products
of fossil fuels. He also showed that there has been a thirty-six percent
increase over the last ten years in the input of acidity to the Hubbard
Brook Experimental Forest in New Hampshire. He explained that this in-
crease is primarily due to an increase in the input of nitric acid from
precipitation. The discussion following his presentation dealt with a
number of subsidiary points that are presented below.
Technique of Measurement of Hydrogen Ion Concentration
There were four possible methods of hydrogen ion determination
discussed: pH paper, pH meter, titration, and utilization of the cation-
anion balance to predict the hydrogen ion concentration. Of the four, the
one that is the most inaccurate is the method of determining pH by pH paper.
An error of several orders of magnitude can result from using this method,
especially if small volumes, such as individual rain drops, are used. The
second method, the use of a pH meter equipped with a glass electrode is
probably the most common method in use today and, if done precisely, gives
*Air Resources Division, New York State Department of Environmental
Conservation, Albany, New York 12233
**Postdoctoral Associate, Ecology and Systematics, Cornell University.
Ithaca, New York 14853
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a good estimate of the hydrogen ion concentration of the sample. The
third method is essentially an extension of the second, in that one begins
by determining the initial pH with the pH meter, and continues with the
incremental addition of a strong base (e.g., NaOH) while monitoring the
pH. This procedure (titration) can give information on the possible
contribution of weak acids and bases to the total acidity of the sample.
The last method, estimation of pH by a cation-anion balance is an accurate
method only if the analytical procedures used to determine the concentrations
of the anions and cations are accurate. It is especially useful when the
detailed chemical composition of the sample is known but not the pH.
Background
Little is known about the background (natural) concentration of any
of the chemical constituents of precipitation. The difficulty of the
determination of these background values is because of the wide spread
effect that man's activities have had on the global environment. It was
agreed that a continuing effort should be made to estimate the background
values for the chemical compounds in precipitation.
Sampling of Precipitation for Chemical Analysis
The question was raised as to the best way for sampling precipitation
for chemical analysis. In response to this, Dr. James Galloway of Cornell
University presented some guidelines on sampling which are the result of
an intercalibration program involving thirteen different designs of
precipitation collectors. The results presented are as follows:
1. For the determination of pH and most of the inorganic ions,
plastic collectors that sample only rain or snow should be used. The use
of a bulk sampler (which collects dry deposition in addition to rain and
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snow) will contaminate the sample due to the inclusion of dry deposition.
2. Glass collectors are required for the determination of organic
compounds.
3. For the determination of trace and heavy metals in precipitation,
the collectors should be made entirely of plastic. This is because of the
strong possiblity of contamination due to the low concentrations of the
metals in precipitation.
4. It is best to sample the collectors after every storm, so as to
avoid changes in the chemical composition of the precipitation. This is
especially true if the pH of the sample is above 5. However, if the
precipitation pH is less than 4.6, the collections may be sampled on a
weekly basis.
Precipitation Networks
The necessity of monitoring the chemistry of precipitation in the
United States was agreed upon. However, the problems of what parameters
to measure and how to standardize analytical techniques are more complex.
Providing that answers are forthcoming to those questions, it was agreed
that the primary factor as to the size and the complexity of the network
would be a financial one.
Correlation of Atmospheric Chemistry and Precipitation Chemistry
It was asked whether, knowing the concentration of the chemicals in
the atmosphere, the concentration of the chemicals in the precipitation
can be predicted. It was the consensus of the meeting that this is not
possible on a quantitative scale at this time. However, rain chemistry
can be used as an indicator of air quality.
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DISCUSSION SESSION ON THE ECOLOGICAL EFFECTS
Jay Jacobson*, Discussion Leader
Don Charles** Rapporteur
At the outset Dr. Jacobson suggested that we divide the discussion
period to allow discussion of three basic topics:
1. Questions on Dr. Schofield's presentation this morning.
2. Research needs on the effects of acid precipitation.
3. What is known and what is not known about the acid rain
phenomenon.
TOPIC I
(Discussion of Dr. Schofield's Presentation)
Dr. Schofield indicated that effects on fish larvae of low pH have
been noted in laboratory studies, but that these studies have not tried
to isolate the particular mechanisms involved.
Dr. Schofield was asked why the higher lakes in the Adirondacks seem
to be more susceptible to increases in acidity.
He indicated this was because there was not as great an input of
cations to those lakes relative to the input of anions (primarily sulfates)
and that this was due primarily to the soils and geology of the higher
watersheds and the ratio of the watershed area to the lake surface area.
Dr. Schofield indicated that he had not found any variation in pH or
acidity in rainfall falling on different geographical areas of the
Adirondacks. He also indicated that the Department of Environmental
*Plant Physiologist, Boyce Thompson Institute, Yonkers, New York 10701
**Project Analyst, Adirondack Park Agency, Ray Brook, New York 12977
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Conservation and Cornell have done some liming of lakes, and that this
liming has resulted in an increase in fish productivity. Additional
changes in the lakes' ecosystems have not been studied to any great extent.
He also indicated that acid resistant strains of fish, primarily brook
trout,have been identified, and that there are generally differences in
populations of brook trout in terms of their resistance to acidity. As
yet, a determination as to whether in fact these are true genetic
differences has not been made. Dr. Schofield felt that most of the fish
that occur in Adirondack waters are susceptible to low pH.
In response to a question as to how well the relationship between
the loss of fish in lakes and inputs of acid precipitation is established,
Dr. Schofield answered that the subject definitely needs further study
and that one of the best ways to do this would be to perform a detailed
materials budget for lakes to determine exactly what materials, including
sulfur and nitrogen, were entering the lakes and from what sources (the
atmosphere or from within the watershed) they came.
The question was asked whether there are additional explanations
for the decreases in acidity in Adirondack waters other than increased
inputs of strong acids from the atmosphere. It was felt that there may
be certain cases -- a natural bog lake, for instance -- where the natural
organic acids have caused the pH to be low, but that in many, many other
cases the only reasonable, most probable, explanation was that the lakes
were acid because of atmospheric inputs of acids.
Then there was a discussion as to how acid effects in lakes might
vary with different successional stages of lakes. Dr. Hultberg indicated
that in Sweden the lakes in a later stage of succession were more
susceptible to changes due to acid precipitation, probably because of the
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oligotrophication (opposite of eutrophication) effects due to the changes
in vegetation in the lakes in later stages. He summarized some of the
effects he had found in the lakes he had studied: new invasion of
macrophytes, particularly sphagnum mosses; extensions of dense fungal
mats over the bottom sediments, and others.
The question was raised as to the possible effects of acid
precipitation on eutrophication. Dr. Fuhs suggested that at least in
terms of algal productivity in the Adirondacks, where most of the lakes
are limited by phosphorus, increased inputs of nitrogen year around may
affect the natural nitrogen limitations that previously occurred in the
lakes. Briefly, in certain lakes in the Adirondacks blue-green algae
appear in late summer, and their populations are generally limited by
phophorus. However, when nitrogen supplies also become low these
species, to the exclusion of all others, are capable of producing their
own nitrogen, and so are able to become the dominant species at that
particular time. If there were increases in nitrogen inputs, then the
more desirable species of algae might be able to compete with the blue-
greens and exist throughout the summer. The magnitude of the shift to
blue-green algae that sometimes occurs would not be as great. This
was essentially a hypothesis based on theory alone, and was suggested as
a topic for further study.
TOPIC II
(Research Needs on the Effects of Acid Precipitation)
The next topic of discussion dealt with those aspects of the
prectpftation phenomenon which people felt deserved further study. I've
already mentioned the fact that Dr. Schofield thought that there should
be very, detailed studies of at least one or two Adirondack lakes to
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determine nutrient materials budgets. He also mentioned that the
Fisheries Research Board of Canada is planning to acidify a lake with
known quantities of acid and study what occurs in the lake ecosystem as
a result.
Dr. Fuhs suggested that we need to know more about what happens to
rain after it falls on a watershed, in its travels to various water bodies;
in what ways is that precipitation modified?
One person suggested that we sould carry out laboratory studies on
the effect of low pH on organisms sensitive to low pH's to determine under
what conditions and by what mechanisms they are affected. The studies
should be designed to determine what synergistic and antagonistic
effects there might be with heavy metals.
It was suggested that more work needs to be done on the effects of
acid precipitation on soil systems including the microorganisms which
inhabit them. More needs to be known about the effects of acid pre-
cipitation on terrestrial ecosystems including forests and wetlands.
Dr. Likens mentioned a recently completed thesis of one of his
students, Charles Cogbill, in which he looked very carefully at a number
of forested areas, including the Huntington Forest in New York State, a
variety of New England forests, the Smokey Mountains, and some others.
Cogbill found rather consistently in most species he looked at that there
was indeed a significant decline in forest growth over the past twenty
years, particularly birch, in some areas. He also found that there was
no way to relate this decline exclusively to any effect of acid
precipitation, that there were similar declines in the past noted from
radial increment growth rings, and that if one examined climate drought
and things of this sort, it was impossible to state that the effects of
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acid precipitation were a causative agent in forest decline and
forest growth. On the other hand he was unable to state that it wasn't
an effect of acid precipitation. I think this is an area that is in utmost
need of further research.
It was pointed out that very little has been done on the effects of
acid precipitation on agricultural crops. But this is perhaps because
in many cases agricultural lands are limed anyway, and because they are
more Intensively managed they could be treated economically. Therefore
the potential for significant adverse effects on agricultural crops is
probably not as great as effects on forests.
Hans Hultberg felt that, as a subject of continuing and further
research, we should define all oligotrophication processes (those in-
volved in the self-acceleration processes causing increasing acidity).
These should be studied with special reference to the time required for
lakes to recover once excessive acid inputs are reduced or stopped. What
recovery problems may occur if we let lakes become too acid, too long?
TOPIC III
(What is and is not known about the Acid Precipitation Phenomenon)
The consensus of the group was that there did appear to be an acid
precipitation phenomenon, and that it deserved further study. There was
agreement that acid precipitation is falling on ecosystems and that this
precipitation is causing changes in those ecosystems. These changes have
been documented in areas such as Scandanavia, the Canadian Shield, and
the Adirondacks.
There was general agreement that in the Adirondacks the atmosphere
fs the most important source of acid affecting aquatic ecosystems; however
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it was felt that some acids may originate in, and be coming from the
watershed. More study needs to be done to determine relative contributions
of these two inputs.
There was discussion as to how much atmospheric sulfur originates
from biological sources and how much comes from man-made sources. There
was general feeling that this subject required further study.
A determination of the precise kinds and physical location of sources
of acid precipitation affecting a particular geographical area needs,
perhaps, more study than any other subject. In terms of deciding whether
or not additional control strategies should ever be implemented and
what those control strategies might be would depend on this type of
information perhaps more than any other.
Dr. Fuhs formulated a series of question statements he felt put
acid precipitation into persepective as an environmental problem. He first
stated that there was very satisfactory documentation that acid
precipitation was falling in Scandanavia and that it was having substantial
adverse impacts on aquatic ecosystems. He then asked whether there are in-
puts to the atmosphere in the United States of acid causing substances
comparable to those documented in Sweden. The question was answered
affirmatively. It was felt also that there have been preliminary changes
in ecosystems in the U.S. that are at least similar to those documented
in Scandanavia and that we can expect that if inputs in the U.S. continue
we may find more effects similar to those which have occurred in
Scandanavia.
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DISCUSSION SESSION ON HEALTH EFFECTS
Donald Casey*, Discussion Leader
Walter Lynn**, Rapporteur
The health effects discussion group concerned itself with a number
of topics which it believes should be pursued in order to better under-
stand and evaluate the possible health effects associated with Acid
Precipitation. Among these are:
1. Improve our understanding of the relationship between ambient
atmospheric conditions, which currently include sizeable amounts of
atmospheric pollutants and precipitation events which reflect the con-
centrations and the quality of ambient air.
2. There appears to be reasonably gross indices of association
between atmospheric pollutants (esp. SO.), but there is need for greater
specificity in these relationships.
3. It's important to develop better health indicators in order
that one can more authoritatively evaluate the effects of acid precip-
itation and air pollutants: for example, physiological indicators
(such as asthmatics) and biological indicators should be explored.
4. There is a definite need for establishing a long-term cohort
study of a sizeable population in order to evaluate the long-term
effects of air pollution and acid precipitation.
* Chief, IFYGL Branch, Rochester Field Office, U.S. Environmental Protection
Agency, Rochester, N.Y. 12746.
**Director, Center for Environmental Quality Management, Cornell University,
Ithaca, N.Y. 14853.
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5. In order to study and to understand the health effects it will
be necessary to establish very strong collaborative groups of disciplines
in order to find answers to these questions.
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PARTICIPANTS
Kurt Anderson
New York Power Pool
3890 Carman Road
Schenectady, New York
12303
Ross H. Arnett, Jr.
Biological Research Institute
of America
Rensselaerville, New York 12147
Connie Bart, Science Writer
Cornell News Bureau
Cornell University
110 Day Hall
Ithaca, New York 14853
Stephen Baruch
Edison Electric Institute
90 Park Avenue
New York, New York 10016
Karen M. Beil
The Conservationist
NYS Department of Environmental
Conservation
5 Lincoln Avenue
Albany, New York 12205
Michael Berry
Office of Air Quality Planning
and Standards
Environmental Protection Agency
Research Triangle Park,
North Carolina 27711
David E. Buerle
Catskill Study Commission
Rexmere Park
Stamford, New York 12167
Donald J. Casey, Chief
U.S. Environmental Protection
Agency,Rochester Field Office
P. 0. Box 5036
Rochester, New York 12746
Donald Charles
Adirondack Park Agency
P. 0. Box 99
Ray Brook, New York 12977
Peter E. Coffey
Dept. of Environmental
Conservation
50 Wolf Road
Albany, New York 12233
Robert L. Coll in, Director of
Environmental Management
Monroe Co. Environ.Mgt.Council
39 Calumet Street
Rochester, New York 14610
Robert Craig
Adirondack Park Agency
P. 0. Box 99
Ray Brook, New York 12977
Raymond Curran
Adirondack Park Agency
P. 0. Box 99
Ray Brook, New York 12977
Robert C. Dalgleish, Director
The E.N. Huyck Preserve and
Biological Station
Rensselaerville, New York 12147
Valentine J. Descamps
Environmental Protection Agency
Region I
255 Weston Road
Wellesley, MA 02181
Michael Dick, Senate Aid
c/o Senator B. Smith, Chairman
Senate Committee on Conservation
Recreation and the Environment
NY State Senate
State Capitol Building
Albany, New York 12224
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PARTICIPANTS
Steve Eabry
Office of Environmental Planning
Public Service Commission
44 Holland Avenue
Albany, New York 12208
Thomas Eichler, Director
Program Development, Planning &
Research
New York State Department of
Environmental Conservation
Room 422, 50 Wolf Road
Albany, New York 12233
Raymond E. Falconer
Atmospheric Sciences Research
Center, SUNY at Albany
9 Townley Drive
Burnt Hills, New York 12021
Peter Foley
Mobil Oil
150 East 42nd Street
New York, New York 10017
Arnold Freiberger
U.S. Environmental
Agency, Region II,
26 Federal Plaza
New York, New York
Protection
Rm. 302
10007
Jean G. French
Human Studies Laboratory
National Environmental Research
Center
Environmental Protection Agency
Research Triangle Park
North Carolina 27711
Peter Freudenthal
Chief Air Quality Engineer
Consolidated Edison
4 Irving Place
New York, New York 10003
John A. Fizzola
Suffolk County Department of
Environmental Control
1324 Motor Parkway
Hauppauge, New York 11787
G. W. Fuhs
Division of Laboratories &
Research
N.Y.S. Department of Health
New Scotland Avenue
Albany, New York 12201
Howard I. Fuller
United Kingdom Institute of
Petroleum
Gl New Cavendish Street
London Wl, United Kingdom
James J. Galloway
Ecology & Systematics Division
Cornell University
277 Langmuir Lab.
Ithaca, New York 14853
Olle Grahn
The Swedish Water & Air
Pollution Research Lab.
Sten Sturegatan 42
Gothenburg 5, Sweden
Frederick W. Hardt
Environmental Associates
Wing Road
Rexford, New York 12148
Thomas E. Harr
Environmental Quality Research
Unit
N.Y.S. Department of Environmental
Conservation, 50 Wolf Road
Albany, New York 12233
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PARTICIPANTS
John Hawley
N.Y.S. Department of Environmental
Conservation
50 Wolf Road
Albany, New York 12233
John Heidelberger
c/o Senator B. Smith
Senate Committee on Conservation,
Recreation and the Environment
N.Y. State Senate
State Capitol Building
Albany, New York 12208
Lawrence Heller
Boyce Thompson Institute
1086 North Broadway
Yonkers, New York 10701
William P. Hofmann
N.Y.S. Department of
Transportation
1220 Washington Avenue
Albany, New York 12232
Hary Hovey, Associate Director
Division of Air Resources
N.Y.S. Department of Environmental
Conservation
50 Wolf Road
Albany, New York 12233
Hans Hultberg
The Swedish Water & Air Pollution
Research Lab.
Sten Sturegatan 42
Gothenburg 5, Sweden
William T. Ingram
Environmental Engineering
Cornell University Medical
College
1300 York Avenue, Room A630
New York, New York 10021
Jay S. Jacobson
Boyce Thompson Institute
1086 North Broadway
Yonkers, New York 10701
Kenneth Juris
New York Power Pool
3890 Carman Road
Schenectady, New York 12303
John Kadlecek
Atmospheric Science Research
Center
130 Saratoga Road
Scotia, New York 12302
Shigeru Kobayashi, Lab Director
Rensselaer Fresh Water
Institute
Rensselaer Polytechnic
Institute
Troy, New York 12180
Gilbert Levine, Director
Water Resources & Marine
Sciences Center
Cornell University
468 Hollister Hall
Ithaca, New York 14853
Gene E. Likens, Professor
Ecology & Systematics
Cornell University
221 Langmuir Laboratory
Ithaca, New York 14853
Walter R. Lynn, Director
Center for Environmental
Quality Management
Cornell University
468 Hollister Hall
Ithaca, New York 14853
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PARTICIPANTS
Robert W. Mason
Region II, U.S. Environmental
Protection Agency
26 Federal Plaza
New York, New York 10007
Robert Means
N.Y.S. Science Service
State Education Department
State Education Building
Albany, New York 12223
Volker A. Mohnen, Acting Director
Atmospheric Sciences Research
Center, SUNY at Albany
Rm. ES 319
1400 Washington Avenue
Albany, New York 12206
Andrew Montz
Office of Environmental Planning
N.Y.S. Department of Public
Service
44 Holland Avenue
Albany, New York 12208
Margaret B. Neno
Center for Environmental Quality
Management
Cornell University
468 Hoi lister Hall
Ithaca, New York 14853
Joseph M. O'Connor
A.J. Lanza Laboratories
Department of Environmental
Medicine
New York University
Long Meadow Road
Tuxedo, New York 10987
Svante Oden
Division of Ecochemistry
Agricultural College
750 07 Uppsala, Sweden
Eric Cutwater, Deputy Regional
Administrator
Region II, U.S. Environmental
Protection Agency
26 Federal Plaza
New York, New York 10007
Herbert Posner, Chairman
Assembly Environmental
Conservation Committee
N.Y.S. Assembly
State Capitol
Albany, New York 12224
Lyle S. Raymond, Jr.
Cooperative Extension
Cornell University
473 Hollister Hall
Ithaca, New York 14853
Boyce Rensberger
New York Times
229 West 43rd Street
New York, New York 10036
H.G. Richter
U.S. Environmental Protection
Agency
Research Triangle Park
North Carolina 27709
Richard B. Ruch, Jr.
Senior Environmental
Meteorologist
Environmental Analysts, Inc.
224 Seventh Street
Garden City, New York 11530
Vincent J. Schaefer
Atmospheric Sciences Research
Center, SUNY at Albany
R.D. 3, Box 36
Schenectady, New York 12306
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PARTICIPANTS
Carl L. Schofield
Natural Resources Department
Cornell University
Fishery Laboratory
Ithaca, New York 14853
Sidney Schwartz, Director
N.Y.S. Department of Environmental
Conservation, 50 Wolf Road
Albany, New York 12233
Janine Selendy, Editor
N.Y.S. Environment
N.Y.S. Department of Environmental
Conservation, Rm 602
50 Wolf Road
Albany, New York 12233
J. Douglas Sheppard
Supervising Aquatic Biologist
Bureau of Fisheries
N.Y.S. Department of Environmental
Conservation, 50 Wolf Road
Albany, New York 12233
Herschel Slater, Chief
Source Receptor Analysis Branch
Office of Air Quality Planning
and Standards
Environmental Protection Agency
Research Triangle Park
North Carolina 27711
Patrick Smyth
Temporary State Commission on
Tug Hill
State Office Building
Watertown, New York 13501
Gerald Soffian
Environmental Protection Agency
Room 905B
26 Federal Plaza
New York, New York 10007
Joseph Spatola, Chief
Air Monitoring Section
Surveillance & Monitoring
Branch
Surveillance & Analysis
Division
Region II, U.S. Environmental
Protection Agency
Edison, New Jersey 08817
William Stasiuk
N.Y.S. Department of
Environmental Conservation
30 Pheasant Lane
Delmar, New York 12054
Gary Stensland
Department of Chemistry &
Environmental Engineering
North Hall
Rensselaer Polytechnic
Institute
Troy, New York 12180
Glenn Stevenson
Scientific Advisory Staff
N.Y. State Legislature
Albany, New York 12224
Vic Stewart, Reporter
Knickerbocker Press
Albany, New York 12201
Diane Stoecker, Assistant Director
Terrestrial Ecology
Environmental Analysts, Inc.
224 Seventh Street
Garden City, New York 11530
Gary Toenniessen, Assistant Director
Quality of the Environment
Program, Rockefeller Foundation
1133 Avenue of the Americas
New York, New York 10036
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PARTICIPANTS
Donald White
Cornell University Regional
Office
Martin Road
Voorheesville, New York 12186
Robert Williams
Institute for Public Policy
Alternatives
99 Washington Avenue
Albany, New York 12210
Sherman Williams, Manager
Health & Environmental
Protection
General Electric Company
P.O. Box 1072
Schenectady, New York 12303
Charles Wolf, Manager
N.Y.S. Electric & Gas Corporation
4500 Vestal Parkway East
Binghamton, New York 13902
George Wolff
Interstate Sanitation Commission
10 Columbus Circle
New York City, New York 10019
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PROGRAM
MONDAY, MAY 19, 1975
5:30 - Welcoming Gathering and
6:30 - Cash Bar
6:30 - Dinner
Presider - Sidney Schwartz
Director of Research
N.Y.S. Department of Environmental Conservation
Welcome - Herbert Posner, Chairman
Assembly Environmental Conservation Committee
Keynote Address -
Acid Precipitation: A World Concern
Svante Oden-, Professor
Division of Ecochemistry
Agricultural College
Uppsala, Sweden
TUESDAY. MAY 20, 1975
9:00 - Plenary Session I
Presider - Gilbert Levine, Director
Water Resources & Marine Sciences Center
Cornell University
Our Understanding of the Phenomenon
Gene Likens, Professor
Ecology and Systematics
Cornell University
Our Understanding of the Ecological Effects
Carl Schofield
Sr. Research Associate
Natural Resources
Cornell University
Our Understanding of the Health Effects
Jean French, Epidemiologist
Human Studies Laboratory
National Environmental Research Center
Environmental Protection Agency
Research Triangle Park, North Carolina
(Break)
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12:00 - Lunch
1:00 - Plenary Session II
Presider - Walter Lynn, Director
Center for Environmental Quality Management
Cornell University
Speakers - Commissioner Ogden Reid
N.Y.S. Department of Environmental Conservation
Eric Outwater
Regional Administrator
Region II
U.S. Environmental Protection Agency
2:00 - Discussion Sections
1. The Phenomenon
Discussion Leader -
John Hawley, Air Resources
N.Y.S. Department of Environmental Conservation
Rapporteur -
James Galloway
Postdoctoral Associate
Ecology and Systematics
Cornell University
2. Ecological Effects
Discussion Leader -
Jay Jacobson
Plant Physiologist
Boyce Thompson Institute
Rapporteur -
Donald Charles
Project Analyst
Adirondack Park Agency
3. Health Effects '
Discussion Leader -
Donald Casey, Chief
IFYGL Branch, Rochester Field Office
Environmental Protection Agency
Rapporteur -
Walter Lynn
(Break)
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